History shows that there are no invincible armies. - Joseph Stalin
The factions in R.U.S.E. includes the United States, United Kingdom, Nazi Germany, Italy, France, and the Soviet Union. Each faction possesses a unique balance of strengths and weaknesses, which allows for more dynamic gameplay/strategy. Japan was added later as part of the Pack of The Rising Sun. The player is able to play the United States campaign in singleplayer. During the United States' campaign you do have a chance to use the UK, France, and German armies, as well as captured Russian and Italian equipment. The other playable factions are playable in the online modes.
United States: Balanced. The U.S. military has units for almost every purpose on the battlefield. They have an average array of both advanced and light units with a massive productivity rate - enabling them to produce high amounts of units on the battlefield quickly. With the U.S. military, strength in numbers is preferable. However, thanks to major advancements late in the war, the U.S. is right behind Germany in terms of technology, which allows for a similar strategy of 'building-up'. Because the US advanced units are still fairly cheap and easy to produce, they can be utilized en-masse as spearheads for large assaults in offensives. The U.S. also is one of the most, if the most mobile faction compared to any other, since their artillery, the M40 is armored and has a tank chassis, the M19 is a fast mobile armored, anti-air unit, that is deadly to aircraft, and the M26 Pershing tank, which is faster and equally armored to a Tiger. This way, the U.S. can attack fast and retreat fast to surprise the opponents. Can counter any other nation if enemy strategy is discovered early.
Germany: Quality Equipment. Though expensive to produce, Germany's units are much more effective than those of other factions, with the exception of aerial units. Their artillery is also very accurate, but have shorter range as a result. Germany has many researchable and powerful units, but they are quite expensive, so proper tactics must be used to prevent the needless destruction of units. German armor is the best on every class, Panzer III dominating the light tanks, Panthers ruling medium tanks, and Tigers are the equivalent to some foreign advance heavies, and the Maus can put a stop to any armor it encounters. Germany's air units are very well equipped and fast: both the Me-262 and the Ar-234 have jet engines, therefore, Germany can shock enemies in the air and ground due to the quality of their units.
France: Defense. The French rely on superior defense in order to win. Their Maginot bunker is capable of putting a stop of an armored and infantry assault in seconds while their fortified position can take on aircraft daring enough to pass through their airspace. They also have an "elite" moniker infantry, the Legionnaires to come out of their barracks. French tanks are useful at the beginning of game and their super heavy tanks are powerful on end game. The French are therefore the most effective way to counter a rush by Italy or by the USA.
United Kingdom: Air Force. The UK has the best overall air force in game. Powerful Spitfire class planes can shoot down most planes with ease, Hurricanes and Typhoons are the best tank killers in the game and the Lancaster bomber has equal firepower as that of the B-17 heavy bomber. Paratroopers do not need research to be fielded. British ground units are not to be ignored, though. They have an advanced artillery force, excellent AA, and good anti-tank, with the Firefly tank destroyers, arguably the best tank hunters in game. However, they have the 2nd lowest useful tank force (just above the Italian armor base), and this can be a disadvantage for the UK and Canadian since their tanks can't fully engage enemy tanks of the same rank.
Soviet Union: Strength. "The best defense is a strong offense." Russia fields powerful units that pack a punch as well as the strongest artillery. The Soviets have spammable basic infantry, as well as the advanced Gvardiya, trained at an incredible speed and very low costs. Tanks are researched early at a high price, but the tanks themselves are cheap, being used to constantly harass the enemy to prevent damage to the backlines. The Soviet Union also have the most varied artillery force in the game. The artillery is already researched and ready to be fielded. With the Katyusha, the infamous Stalin Organ, confusion is spread on a wide scale with maximum ranges far behind enemy front lines. The Soviet Air Force is also quite effective against ground targets, although it needs protection against enemy planes. Russia's AA only works well when spread in massive numbers with a mix of AA guns and fighters. Russia also has a very effective super-heavy tank in the IS-3, arguably a better upgrade to the IS-2, even though it is more expensive.
Italy: Speed/Superior Numbers. Italian units are weak, but cheap to build, take almost no time to construct, and are much faster than equivalent units from opposing factions. The Italian war machine relies almost completely on maneuverability and superior numbers whilst in combat. Italy (having the strongest air defense) is the counter to the UK. They have 2 ultra heavy AA/AT units, a light AA unit, and a super AA unit. These guns will tear the British air force to bits. Similarly, their many tanks can survive constant attacks by British fighter-bombers.
Japan: Wild Card. They have very good air units similar to the British. Likewise, their tanks typically lack armor but make up for it with higher firepower and speed, similar to Italy. Japan also has a variety of Infantry. Japan is a wild card, they can pretty much take on any nation, but they can in turn be beaten by any nation. They have one good anti-tank. For a quick rush strategy, Japan can pound out $5 tanks, as long as the other team doesn't have a good enough anti-tank force to stand out against those tanks.