Speaking as a U.S. Citizen:
Actually, the bourgeoisie use a number of tactics to influence politicians. Sometimes they contribute to one candidate, other times they contribute to both candidates, and then sometimes they wait and see who wins before contributing. But there are times where vested interests will intervene in the electoral process to make certain the sure bet wins out, as was the case in the 2000 presidential election.
That's why appeals to "lesser evilism" are, as already stated, a bad tactic. Think of the presidency like any other job under capitalism, despite how "nice" the person is or what their intentions are they still have to carry out the boss' orders.
But now we must pick up every piece
Of the life we used to love
Just to keep ourselves
At least enough to carry on