the Democrats did this to themselves! Both the elected Dems and every Democratic voter who didn't vote. In the former case, imagine how different this election would have turned out if the following were true:
1) Gitmo went back to being a Marine base and not a detention center.
2) Medicare-for-all had passed
3) Glass-Steagal had been resurrected and Wall Street once again had rules-of-the-road.
4) Warrantless wiretaps had been discontinued.
5) There had been a REAL jobs-program WPA-style.
Would the Republicans have still picked up seats? Probably. But they would have been facing a Democratic electorate that felt that too much had been achieved to let it be rolled back. What's more, the Tea Party/Republicans would have done PRECISELY what they did anyway. If Obama had actually staked out some position so far to the Right that he made Joe Miller or Sarah Palin look like full-on Marxists, the Tea Party/Republicans would have STILL called him a Marxist, they'd STILL call him a socialist, they'd STILL say he wasn't born in the United States and they'd STILL say he was in league with terrorists. There is NOTHING that man could do that would please the Tea Party. The same applies generally to the Democratic party. If the Dems eliminated every single social program, repealed the Voting rights act, passed a law making Islam illegal, repealed the Civil Rights Act and did away with the income tax (or just put it all on the backs of the poor), the estate tax and the capital gains tax, the Republicans would still insist that Democrats were un-American, tax-and-spend liberals who hate America and want the terrorists to win. If the Democrats voted to bomb every square inch of land in an arc from Istanbul to Jakarta the Republicans would still say that the Democrats were 'soft' and 'unwilling to fight'.
So what, precisely, did all of these misguided attempts at bipartisanship get them? Nothing. What did all these compromises get them? It got them beat like a red-headed stepchild that stole something, that's what.
When I was in grade school, I got bullied mercilessly. I got bullied for being black. I got bullied for being gender non-conforming. I got bullied for being a geek. I got bullied because the sun shone light upon my face. I learned, really early on, that you cannot show weakness to bullies. You cannot let bullies know you *care* what they say about you. IF you do, you hand them encouragement and ammunition. The Dems, in deciding that they would care what a party that made it clear that their ONLY real agenda was the defeat of the Democratic party--and if the country has to burn or that to happen, so be it--thought they doomed themselves.
Now, was any of that an excuse to stay home? No. It wasn't. Anyone who thinks that there is no substantive difference between the agenda of the Democratic party and the agenda of the Republican party isn't paying attention to either party platform. The Republican party appears to believe that even if you are raped by your own father, you should be forced to have the baby. The Democratic party doesn't. The Republican party appears to believe that America should be *actively* hostile to homosexuals. The Democratic party does not. The Republican party appears to mean that 'freedom of religion means the freedom to practice whatever brand of Christianity suits your fancy'. The Democratic party believes freedom of religion means just that--the religion of your choice or no religion at all. The Republican party believes that if you just cut taxes enough, you'll increase tax revenues. The Democratic party seems to have some nominal grasp on mathematics.
To paraphrase the Bard; the fault, dear Democrats, is not in the stars but in ourselves.