A fundraising appeal from President Barack Obama on Monday netted Democratic Congressional candidates their biggest online fundraising day ever, New York Congressman Steve Israel said at the Reuters Washington Summit.

Obama made an email appeal asking supporters to donate $3 or more to help the Democratic Congressional Campaign Committee. The appeal raised $580,000, said Israel, chairman of the DCCC, which helps recruit and raise money for candidates for the House of Representatives.

“Our base is animated, engaged, writing checks,” Israel said. “Our grassroots participation is absolutely off the charts.”

Obama’s brief email contained the suggestion that “if you’re with me, then I need you right now. We’re just days away from the mid-year fundraising deadline — this is the biggest test yet of our commitment to win in 2012. We can’t fall short on this one.”

Israel said small checks have been flowing into the committee’s coffers recently. “A few weeks ago a guy sent us his World War Two war bond,” he added.