In my opinion, a part of the blame belongs to the American people for electing these non-proficient people, to begin with. Far too many Republicans and Democrats are straight-ticket voters. Hence, little to no research goes into the person they're voting for. So they end up with someone they wish they hadn't voted for.
I understand what you're saying. However, even though we don't have much say in who they put up, we can still research the candidates that they do put up.. Check out their history. How they voted on the policies that you care about. And to see whether or not their policies are what's best for your state and the country as a whole.
That said, some candidates may say one thing during their campaign and do a very different thing when they later are in office. There’s little we as voters can do about that. But if we see signs of poor character during their campaign and still choose to give them our vote? Then we are to be held responsible. So, what are we to do?
For me personally, if both candidates are of bad character and/or a shady voting history and I know that upfront, then I can’t honestly choose the “least bad” of the candidates. Instead, I either won't vote or I'll vote for a minor party candidate that holds to the policies that I agree with and what's best for my state and country.
What you say is very true, and I was going to reply that what they tell you on the campaign trail and what they actually accomplish in office can be two different things. We have to remember that they can't enact legislation individually, so if their policies don't go over with their party or other politicians, they become ineffective.
I'm sure that many of us, including me, have voted for the least objectionable candidate when both are unappealing. Then I will vote party. By voting for a minor party candidate, it's like not voting at all.