It's all play acting. They figure out how many votes they need to satisfy the people with the money, and any excess is allowed to vote the other way. Let's sa

It's all play acting. They figure out how many votes they need to satisfy the people with the money, and any excess is allowed to vote the other way. Let's say the Congress wants to pass something the banks like, and they have 50 more votes than they need. The party leaders figure out who represents districts that won't like the legislation and those representatives get to vote against. In the end it's a super close vote, on paper, so 49 Congressmen can go back to their district and say "Gosh, I did my best, but we just couldn't stop it." Look at the Iran deal. Treaties need 60 votes to pass the Senate. Now, Republican voters don't like the treaty, but the Republican establishment wants it to pass. So what do they do? They pass a bill that assumes consent and sets up a second vote that will only stop the treaty if 60 vote against it. Then they go back to their districts and pretend the second vote was the real one.