John McCain’s presidential hopes seem to be fading fast. Now there’s speculation that he could drop out of the race by September, a remarkable turn of events for the onetime front-runner.

I’m sure there are many things to blame for McCain’s plummeting poll numbers, but nothing has done more damage than his support for the Senate amnesty bill. McCain’s alignment with President Bush and Sen. Teddy Kennedy (D.-Mass.) on immigration is a non-starter with conservatives. It appears to be also having a significant role in his second-quarter fundraising struggles (we’ll know more in about a week).

To make matters worse, conservatives in his home state of Arizona have taken up a petition calling on him to withdraw from the presidential race. Ouch!