Worgen said:
Oh sure they signed a peace thing but that wouldn't matter, people would want blood. Hell, we invaded Iraq because 12 idiots crashed planes into us, even if there was a peace treaty, it wouldn't last long. If the current pres didn't want to invade he would be impeached and removed. People would want blood, a lot of it.
And that is why it would be make for an interesting plot, every cod game has america on the defensive, this would finally be one where we started out purely on the offensive and pretty much doing all the things that the bad guys in cod games do. Because we would want blood.
I don't think there's really anything to say concretely that that's how the politics would go in the aftermath.
For starters, over three months passed between rescuing the Russian president and the final mission to kill Makarov. From what I remember, Price's speech presumably came shortly before the events of taking out Makarov, and I'd imagine three months would give him the chance to gauge how stable the peace was. Considering it looked relatively bright, I think we can say there wasn't some massive coupe in the U.S. to overthrow a government that wanted peace, nor was there some attempt by Congress to force a war the President didn't want. At most, the concern was on a single terrorist, which at the time was simply Makarov. Now, there could be an American terrorist who plans to attack Russia, but they sort of already explored that option in Modern Warfare 2, and any future story would seem somewhat redundant.
Second, there's a very good possibility the U.S. was tired of war. We've seen plenty of this in the last decade: Many people become tired of being at war. In the Modern Warfare timeline's span of about six years, we know of the U.S.'s invasion of a Middle Eastern country that ended with 50,000 soldiers being killed in a nuclear explosion, a war in Afghanistan that had been going on for who knows how long, an invasion by Russian forces that at the very least left the entire East Cost in shambles, a war in Europe that claimed even more lives in a short amount of time, and a few other minor skirmishes that we either saw or heard about. Heck, we don't even know if America has enough of a government to properly function, considering no one knows how the politicians in D.C. fared after the invasion. And that's not even counting all the members of Shadow Company that were either killed or certainly labeled as traitors. Provided the U.S. even has the manpower to launch another invasion, it is very possible that most, though certainly not all, people in the U.S. would want to just see an end to war.
Now, it is possible that other stuff could go on in the Modern Warfare universe. I think it would be nice to see a spinoff game that explored what happened during the invasion on the West Coast a little more. It's also never fully explained what happened to the members of Shadow Company (at least from what I remembered), and that really disappointed me. However, I just don't see a future invasion of Russia. If anything does happen post-Peace Treaty (outside of Price and Yuri launching a final mission to kill Makarov), I'd imagine it would have to do with either a third-party nation trying to take advantage of everyone else's weakened states, or we'd see a group of extremists who do want blood creating a problem in one of the weakened nations. Seeing anything on the scale of MW2 or MW3 seems unlikely, which is also probably why we may never see another game from the series. The Modern Warfare trilogy was built around taking set pieces to the extreme, and after how far they went with MW3, they would probably have a hard time taking things further.