If you really want to win your race for the U.S. Senate, then resign your current office as governor and fight for it. You can't give people mixed messages, and a convenient reason to vote against you.
If you are as popular as the poll say, it is an easy choice to "send Obama a message" by voting Republican, and keeping you as their popular governor.
If you lose now, you will lose if you try again in 2012. Losing is contagious. Plus there will be more Obama haters in 2012. After that, your career is pretty much over.
If that doesn't matter to you, then why are running?
I'm assuming it does matter, so resign now, and give yourself the best chance.
Up or Down on you and not Obama.