It is the year 201X. The evil communist Russian Federation has launched a surprise attack on US soil, somehow managing to sneak an entire army's worth of men and equipment over the Atlantic Ocean through reasons unknown. The reason was unclear, although one thing was: the United States was now at war. Emperor President Donald Trump has ordered that the US military fight the invaders, and drive them from the US before the dreaded China decides to join in. The war has dragged on for many months without any signs of stopping, and now most of the West Coast of the US is being torn apart by war.
You are Private James Davis Smith, a soldier in the United States Army. For the past few weeks you and your unit, the 1st Infantry Division, have been holding back the Russian invasion in Washington, but you question how much longer you can last. Around you are your fellow soldiers, and the bodies of the fallen. You wipe some blood off your goggles and pop your head out of cover.
You are greeted by the sight of a red sky and thousands of tracer rounds from AA guns being fired at aircraft up above. Burning buildings are all around, and you can see defenders holed up in the White House. President Trump had been evacuated months ago, now likely safe and sound in his super secret presidential holiday mansion in Palm Beach, Florida. On the ground and behind various pieces of cover are your sworn enemies: Russian troops. They are all wildly firing their AK-47s at your general direction, the lenses of their gas masks reflecting the fires.
"Ramirez!" You hear an African-American sergeant shout in the distance. "Destroy that BTR with this Javelin!" A second later, a missile streaks down from the sky, blowing up an attacking BTR. You duck back into cover as a bullet whizzes by, take a breath, and take a look at the weapon in your hands.
It is a [INSERT WEAPON HERE], making you a [INSERT SQUAD POSITION HERE].
 M4A1, rifleman
 M249, automatic rifleman
 M16A4 with M203, grenadier
 M14 EBR, designated marksman