Why today was a good day for Barack Obama.

Every day until the election, Slate will offer up one reason to be optimistic for your candidate.

13 days to go:

Today’s Good News for Obama: Following his raved-about keynote address at the Democratic National Convention, Bill Clinton has been hitting the campaign trail for Obama and other Democrats in recent weeks, and he’s preaching the gospel of liberalism to voters across the country. He’s also been acting as an Obama surrogate, praising the president’s foreign policy and debate performances and casting his first term in a generous light. Whatever tension once existed between the 44^th and 42^nd presidents seems to have evaporated, and Clinton is clearly dedicated to the task of transferring his 66 percent favorability rating into Democratic votes. If Obama is finding running on his own record isn’t enough, it’s nice to have Bubba in your back pocket.

See Barack Obama’s earlier rays of hope.

See Mitt Romney’s earlier rays of hope.