From the man himself:
I am running for the US Senate because we deserve a Senator who will stand up for Connecticut and stand up for our progressive democratic values. Rather than spending hundreds of millions of dollars a day in Iraq, it is time for America to refocus on issues back home: fixing our health care system, upgrading our schools, and rebuilding our aging infrastructure. We will start winning in Iraq as the Iraqis take control of their own destiny, just as America has to start investing again in our own future.
I would have led the opposition to Judge Samuel Alito's nomination to the Supreme Court, which may soon be considering the South Dakota law which outlaws a woman's right to choose even in the case of rape and incest. I will push for energy conservation and efficiency standards as the best means to energy independence and a cleaner environment.
In other words, I am running to be your Democratic Senator.