If you're a US citizen, there's a very high probability that today is election day for you. (A few states and localities hold their off-Congressional-cycle elections on days other than the first Tuesday after the first Monday in November.) Do your duty and vote.
It does matter whom (and what, in the instance of referenda and initiatives and such) you vote for. It matters even more that you vote at all: That is, ultimately, why every American veteran is a veteran. As shameful as some of the particular policies and interventions over the years have been, it's all ultimately in protection of the US Constitution and the right to vote — none of the rest of it happens without it.
And for international readers, and US readers whose elections are on a different date: Do your duty when it's your turn. As Archie Tuttle says, we're all in this together. Even when we can stand each others' views.