Hearts of Iron 4 (HOI4) – USA Strategy Guide

During the Second World War, one country managed to change the course of the whole world with the creation of the most powerful weapon known to mankind.

The United States of America may have consolidated its power as the strongest country in the world during the 1940s, but it starts very weak in the 1936 Hearts of Iron 4 start.

Plagued with debuffs left and right, the USA has to fight a lot of internal problems before even thinking of joining WW2 against Germany and Japan.

In this guide, we will show you how to quickly fix the problems of the USA and mobilize the economy to fight and win WW2 in Hearts of Iron 4.

Table of Contents

General Strategy for USA in HOI4

The main problems that the USA has at the start of HOI4 are the Great Depression and its government laws.

The Great Depression, Disarmed Nation, and Undisturbed Isolation all limit the capabilities of the United States, making the country with the highest Civilian Factories count at the start of the game one of the hardest to mobilize.

The main goal of a USA player is to quickly get rid of these three horrible debuffs, which will allow them to build hundreds of Military Factories in just a few years, allowing the country to immediately end the Second World War.

The other important part of playing the USA is the Navy. However, many players have been able to win games without ever looking at that part of the game, so it all depends on preference.

Marines (and Amphibious Tanks) will be a huge part of the strategy, as the main role of the USA is the D-Day.

They can never join the war soon enough to put troops in Europe, and they have to land in Japan, Sicily, and France to end the war in favor of the Allies.

One other part of the army that will be important is the Air Force, which will be able to help the Allies throughout the whole war, either as fleet bombers or as CAS for the Naval Invasions.

How to Start as USA

The first step that USA players will need to take is to immediately pick the Medium Lobbying Effort decision.

Since Political Power will be a huge problem due to the Great Depression, players won’t have the ability to select any of the Lobbying decisions due to them reaching negative PP growth.

However, selecting the decision before choosing a focus for the country will allow them to gain 10 Senators and 50 Representatives in the first 45 days of the game on their side.

Since most of the focuses that fix the country add opposition in Congress, this is the best way to start.

After that, the focus will be on getting rid of the three debuffs that plague the country and building Infrastructure to increase Resource production.

National Focuses

When it comes to the focuses of the USA, players will have to make sure they always have enough support from the Senate and the House, since they can’t mobilize the country fast enough.

There are 5 national focuses that you will need to take to fix the country and start beating Europe however you want: Agricultural Adjustment Act, Fair Labor Standards Act, Federal Housing Act, Selective Training Act, and The Giant Wakes.

Once you pick up The Giant Wakes, there’s nothing stopping you from becoming the greatest power in the world.

Here are the focuses to pick as USA in the first years:

  1. Continue the New Deal
  2. WPA
  3. Agricultural Adjustment Act
  4. Suspend the Persecution
  5. Reach out to the Wave Group
  6. Scientific Research & Development Office
  7. War Department
  8. Fair Labor Standards Act
  9. Selective Training Act
  10. Neutrality Act
  11. Arsenal of Democracy
  12. The Giant Wakes
  13. Federal Housing Act


USA starts off with the largest number of Civilian Factories in HOI4 but with horrible debuffs to construction of new factories.

It also has an incredibly low count of Military Factories, which means that we will need to do some strategic planning to make sure we can increase these by the time we can join WW2.

Luckily, the USA has all the time in the world to prepare since players won’t really have anything interesting to do for 70% of the game.


Due to the horrible Undisturbed Isolation economy law that the USA has, players should never build Civilian Factories, Military Factories, or Naval Dockyards at the start of the game!

Until we change that law, we would be just wasting a lot of construction costs on nothing.

This is why the only thing that we’ll build until that’s fixed is Infrastructure. But, we are going to be smart about it, we are going to improve states that produce valuable Resources in abundance.

We recommend maxing out the Infrastructure in these states:

  • Texas
  • Nevada
  • Arizona
  • New Mexico
  • Utah
  • Idaho
  • Michigan
  • Minnesota
  • North Dakota
  • California
  • Tennessee
  • Oklahoma


The first thing you need to do is remove the Basic Small Airframe at the end of the Production line list and replace it with Carrier Naval Bombers.

Though Fighters can be useful in some situations, the true powerhouse that gets rid of enemy fleets are Naval Bombers.

Next, we will need to rearrange all the boats that are in production at the start of the game. Just drag all of the 5 Carrier boats in production at the end of the line and then make sure to fill up the Naval Dockyards for all the ships.

This way, when you get new Naval Dockyards, they will go into speeding up the build speed for smaller ships, allowing you to quickly finish all of the Destroyers and then only finish the Carriers with your full industrial power.

Now, here’s how you should use your small Military Factory industry:

  • x3 Infantry Equipment
  • x2 Trucks
  • x2 Support Equipment
  • x1 Towed Artillery
  • x1 Towed Anti-Air
  • x1 Carrier Naval Bombers

The United States of America is one of the only countries that starts with more than enough Trains and which will never get bombed enough to actually lose them.


First of all, make a huge Navy with all of your ships and set it to do Naval Exercises.

Since the USA has a huge number of ships, big enough for most players to just give up on building new boats and handle WW2 with those, the amount of Navy Experience gained from the exercise will be huge.

Basically, USA players have an “infinite” source of daily Navy Experience which will never be in any trouble for most of the game.

You can do the same thing with the Air Wings since you won’t really have any problems with getting fuel for them, and you can farm Experience many years until Japan attacks you.

For the land army, change all the divisions into the National Guard divisions and train them. Constantly improve the division template by adding extra Infantry to allow you to farm more and more Experience.

Otherwise, there’s nothing to do with the US military until around 1940-41.


The Congress will be extremely annoying, as people will just constantly oppose your push to save the industry of the US and start actually preparing for war.

The main solution to beat the Congress and pick whatever national focuses you want is to press the Medium Lobbying Effort every time you finish a focus right before picking a new one.

You need at least 0.3 Political Power daily increase to pick the decision, and selecting a focus will result in a 0 increase per day.

By starting the decision before picking the focus, you will have to accept that you will make negative Political Power for 45 days, but you’ll have the support of the Congress.

Otherwise, just accept most of the events that want you to do something in exchange for support and fulfill your promises.

Waking the Giant

So, if you manage to follow the national focuses list we made earlier, then you should be able to complete The Giant Wakes focus around April of 1938.

This means that Germany should have just finished its Anschluss, and you will be ready to build the largest economy in the world.

Also, make sure to keep the Democrats in power for the whole game since this is just the best way to quickly get rid of the negative debuffs.

For the start, we will just focus on increasing Experience in all fields and increasing support in  Congress.

Once you complete the Agricultural Adjustment Act focus, there will be enough Political Power gain to actually get some points while Lobbying Congress. Generally, avoid using Political Power on Advisors until we get rid of the Great Depression.

The only Political Advisor that would be acceptable would be the Silent Workhorse since he will increase the Political Power gain.

Otherwise, the Reach Out to the Wave Group focus will give the USA three free Political Advisors to pick from. Harry White will be an amazing addition to the advisors list since he will lower the Consumer Goods Factories factor by 15%.

Improving the Army

During the time you’re waiting for focuses to complete, start using the Navy Experience to improve ship templates and maybe even consider refitting some of the old parts of the Navy into the new templates.

Also, work on getting the Doctrines for the Marines to make sure that they are as powerful as possible when the war starts while also making some good, optimized templates for them.

Generally, if you want to build ships to help in the upcoming war, focus mainly on Destroyers and Cruisers since those will actually get built before the war starts, and you have more than enough heavy ships.

Building Factories

When most of the Infrastructure is done being built, players can start building Civilian Factories all over the country. We will keep building Civilian Factories until we finally complete The Giant Wakes focus.

Once we get rid of the horrible debuff from Undisturbed Isolation, just leave the Civilian Factories that started building finish and start building only Military Factories.

Sino-Japanese War

Usually, around the time players start the Selective Training Act focus, which will get rid of the Disarmed Nation conscription law and give the US +10% War Support, Japan will attack China.

To complete The Giant Wakes focus, players will need at least 30% War Support. You will already have 5% from the Pride of the Fleet. The focus will give you +10%, and sending an attache to China will give you another 10%.

This means that you will be 5% War Support away from picking the Wake the Giant focus. That 5% will usually come when either Spain ends its Civil War, when Germany does the Anschluss, or Japan attacks China.

World Tension will need to be 13% for War Support to increase by 5%, giving you exactly what you need to mobilize early and wake the giant up.

When WT finally gets where we want it to, we rush The Giant Wakes, change the economy law to Partial Mobilization, and complete the Federal Housing Act focus afterward to finally get rid of the last debuff, the Great Depression, from the great USA.

How to Win WW2 as USA

Preparing for the Inevitable

Now that the giant has woken up, start creating an Intelligence Agency. Before getting rid of Undisturbed Isolation, players should never work on their Intelligence Agency as the USA. Otherwise, you would have to suffer from a +100% debuff to upgrade time in the Agency.

Since most of the war will take place in the Pacific, you should start building Railways in the Philippines to make sure that you have supply for your advance divisions.

Otherwise, you would have to rely solely on supply from Convoys, which will get decimated by the Japanese.

You should also build high level Naval Bases and an Air Base to keep most of your planes that aren’t placed on top of Carriers.

When it comes to the army, 5 full armies of Infantry with Artillery, 2 armies of Tanks, and 1 army of Marines should be more than enough to capitulate Japan.

Prepare Naval Invasions from the Philippines, using the Marines, Tanks, and some of the Infantry divisions, to conquer Nagasaki, Osaka, and Taiwan.

Taiwan will be more of a secondary plan since we will need it if the two first invasions fail to push from closer to the mainland.

Fighting Japan

So, Japan will either directly declare war on the Philippines or on the USA. In either case, this will happen around 1941 or 42. If they quickly defeat the Chinese, they will attack the Allies, and you can join the war by joining the Allies.

Either way, Japan will be very easy to defeat. Split your huge Navy into two giant fleets, both set on Naval Invasion Support in South China Sea, East China Sea, Philippine Sea, and Coast of Japan.

Set up the Naval Bombers stationed in the Philippines to Naval Strike the same areas to start weakening the Japanese Navy.

After making sure that your fleet is at full power and that you have Naval Supremacy in the region, start the Naval Invasions into Japan.

If you manage to get even one port in mainland Japan, the war is done. There is no way they can come back to stop you in their home territories, and they will capitulate relatively quickly.

Generally, Japan will have too many troops in China or Indochina to stop a full army walking through their capital.

The main focus of this war will be holding the Philippines. If you somehow lose them, it will be very hard to launch a Naval Invasion in Japan.

If you don’t manage to get any of the ports in the mainland but get Taiwan, start preparing a new invasion from there into Kyushu, with all of your Naval and Aerial forces focusing on the East China Sea.

Ending the Axis

Though we’ve made Japan our main focus, Germany is the actual main villain of the game.

The problem is that Germany will generally weaken itself in time by fighting the Soviets. However, Japan has no