At an early evening rally in Leesburg, Virginia on Wednesday, Barack Obama did his best to try to convince his supporters not to get ahead of themselves, forecasting a tough fight in the remaining 13 days of the election.

“We can’t let up, and we won’t let up,” Obama vowed. “Because one thing we know is that change never comes without a fight.”

Later in the speech, he began to say, “If I am president…” before getting cut off by cheering supporters who didn’t approve of his leaving any doubt about it. “No, no, no,” he shouted back. “I’m superstitious, I don’t like counting those chickens.”

Given the criticism he’s endured for being hubristic, and his experience of watching his double-digit lead in New Hampshire polls leading into the primary evaporate overnight, his tone is understandable. The campaign, no doubt, doesn’t want to see turnout dampened by voters who think that Obama already has the election in the bag.

I spoke to a handful of supporters while leaving the rally who showed the same cautious optimism.

“I want him to win, but I’m not going to take anything for granted,” Brenda Cannady of Dumfries, told me. “It looks like from the polls that he is ahead, so I have hope that he’ll win.”

Janet Scott of Fairfax, who was there with her daughter and said she has never been as excited to vote for a candidate in her entire life, was a bit more bullish on Obama’s chances.

“I’m completely confident,” she said, though she added, with a chuckle, “Then again, I was confident last election, yet wrong.”