I'm not sure if aggressor would be the right word to describe either country in terms of their relationship with one another. They can both be aggressors, when it comes to how they treat other countries, but not with each other. Neither is really attacking the other. If it is true that Russia influenced the US election, then that is not a good thing, but it shouldn't be considered aggression, I don't think. The US has introduced a lot of sanctions against Russia, but these are mostly based on Russia violating international laws by occupying Crimea. Even if Crimeans really want to be a part of Russia, Russia went about the annexation wrong. A lot of the "conflict" between Russia and the US is just a show to distract us from the bad things each government is doing within its own country.