Speaker John Boehner is in this fight alone and is constantly looking over his shoulder to make sure the voters, as has been done in the past, don't stab him in the back.
In November if he loses seats, he may still remain the Speaker, but this has in effect weakened his stance and his positioning to continue to resist the White House. If he gains seats then this is giving him a message to continue to fight the White House and Senate for us.
In other words, don't listen to the polls, get out and vote for your Representative and Senator.