I fully intended to continue these series on a weekly basis but other things made it difficult to make an article and I'm sorry for missing 2 weeks back to back. So to make up for it I'm combining 2 articles into one and we're going to cover all rarities in the US. Next week I can hopefully get back into the weekly schedule without further delays.
M8 Greyhound - For only 1 kredit this does a surprising amount of work. A 1/3 blitz tank is on it's own a decent card and this is helped by how some USA decks care about controlling the frontline. Cards such as the M4 Sherman (which is just a little farther down in this very list) are strong rewards for having units in the frontline and the Greyhound, being so cheap, makes having the frontline possible very early on. On top of that, the support line buff the greyhound gives also makes it useful in decks that are running a lot of artillery and air units. There is even the possiblity to run in decks that don't care about the frontline simply to have a decent early unit to help against things like aggro.
Awoken Giant/Gunship Mission - There two cards are being combined becuase usually where one is run the other is also. Awoken hitting only the frontline and Gunship hitting the support line means that when both get run to give US decks the ability to have removal against most units. There are some decks that only choose to run one becuase of various reasons. For example frontline decks won't really want awoken giant since they plan to hold the frontline but gunship is very useful since it can be removal and also has the small bonus of being able to hit the enemy HQ which can help in finishing opponents off. For early game removal either card is a good choice but it's often useful to have a mix of both to cover a wider range of threats.
5th Infantry Regiment - It probably isn't surprising that this is mainly going to be used in a frontline deck. A 2 kredit 2/3 isn't an awful statline on its own and when it moves into a frontline a 3/4 for 2 kredits is very strong. 4 health is not easy to remove on it's own and don't even bother trying to be efficent while doing so. All the removal that would deal with it are going to at least be 3 kredits and no other unit at 2 or less kredits can kill it in one attack. This makes the 5th brigade a very strong choice in frontline decks due to it's ability to hold the frontline. It also happens to fit very well into the curve of most frontline decks becuase it can be played on 2, take the frontline on 3 (along with leaving you 2 kredits to do as you wish), and likely survive to trigger the M4 Sherman on turn 4 which is likely the best pay off card in US frontline decks.
Naval Task Force - Flexibility is always a useful thing to have in a card. This is why orders that can hit any unit in any line are often more powerful than ones that are more narrow in their use. Naval Task Force gives a lot of flexibility in what it offers based on how the game is going. If you’re ahead and have the frontline then supply shipment is great at further pulling ahead as you make a unit in the frontline significantly stronger. However, for those times you’re behind the enemy you can use the naval bombardment to bounce an enemy unit to the enemy hand to hopefully even the board out. The naval bombardment can even be useful to bounce a guard to let you kill the enemy HQ. There is a problem in that you first have to pay for naval task force itself which makes quite expensive to play it and the other card in the same turn (either 4 or 6 kredits which can limit what you do with your units). The best way to mitigate this is use naval task force on a earlier turn you have 2 extra kredits; that way the card you choose is cheaper when you decide to use it.
F4F-4 Wildcat - Giving your HQ smokescreen is essentially a super guard since it stops any unit from attacking the HQ. So the question is if a 3/3 fighter with a better guard worth playing in a deck? With a lack of other guards the wildcat fufills a role that is very important for slower USA decks. The USA has some of the most overwhelming late game cards so having anything to help make it there is very useful. A 3/3 fighter for 3 kredits with some upside has proven to be good with various other fighters (although the other examples ended up nerfed a long time ago for being actually to strong). It may not be strong enough to get nerfed but the wildcat is defiently worth playing when you need to some defense.
M4 Sherman - The big payoff in USA frontline decks because it is amazing card draw stapled on an alright tank unit. It is limited to USA as a main nation since it requires a US unit to have the frontline to trigger but that isn’t a hard thing to deal with if the right deck. Cards I talked about previously like the Greyhound and 5th Infantry are great units to enable the Sherman due to their cheap cost and tough stats. It is a fantastic unit that when played on curve ensures you have a nice big hand heading into the mid game. It allows decks running it to keep playing units without running out steam before they can win. If you plan on playing a US deck that wants some amount of units in the frontline it’s often good to run at least a few copies of this powerful tank.
Unity is Strength - The maximum buff unity can give a single unit is +9/+9, but even getting something like +3/+3 is quite strong. There's a couple decks that are able to play a lot of infantry and likely the obivious deck to get the most out of unity is soviet tokens. With them playing so many 1K infantry it's quite easy to make unity give +5/+5 or more and can lead to massive damage out of nowhere if they attack the HQ with that unit. Unity is a card that at least in terms of well defined decks is quite limited to soviet tokens as it's main home but some other aggressive could use it also. Japan for example has a lot of cheap infantry and many have low operation costs and fury making them amazing targets for unity. Outside of those types of decks though unity doesn't find much use so if you decide to craft this make sure you have a clear defined place for it.
1st Marines - This is one of the few units that works well in slower US decks and also being useful in frontline decks. Blitz is the key piece that makes the marines so useful becuase it allows the marines to be proactive no matter what the board looks like. If you're behind the blitz allows you to hopefully kill an enemy unit in the frontline and if you're ahead you get another unit to push into the frontline. On top of that the 1 turn smokescreeen can be useful to protect your HQ against stuff like bombers or artillery which can on occasion let you comeback in the game.