President Barack Obama praised Congressional Democrats on Thursday evening for their “tenacity and fierce urgency— in helping him bring about sweeping change during his first six months in office.

But, he said, much more remains to be done.

Speaking at a joint Democratic Congressional Campaign Committee and Democratic Senatorial Campaign Committee fundraiser at the Mandarin Oriental Hotel in Washington, D.C., Obama said Democratic leadership in Congress and the White House is moving the country in the right direction.

“We can see some light along the horizon but we’ve got a much longer journey to travel,— he said, according to pool reports. “And this is when it gets hard. Ironically, in part because the economy has stabilized somewhat.—

That, he said, is “why I’m here tonight, because I can’t bring about the change that I promised by myself in the Oval Office. … I need partners in Congress.—

The dinner was the first fundraising event Obama has headlined for the two Democratic campaign committees.

One of the issues that Obama said he would need Congress’ help to address is health care reform. He had some harsh words for critics of Democratic ideas for health care reform who have yet to offer ideas of their own.

“I have to ask, what’s your answer?— he said. “Don’t tell me that all you’re offering is meager tax cuts to uninsured Americans. Don’t present that as a new idea. … Don’t tell me that we’re going to tinker around the edges and that nothing’s going to change.—

Thursday night’s dinner made just as many headlines for who wasn’t invited as it did for its keynote speaker.

Per Obama and the Democratic National Committee’s fundraising ground rules, the DCCC and DSCC were barred from raising lobbyist and political action committee money at the event. Some Democratic strategists said the fundraising restriction is a major reason why the committees were expected to raise just $3 million from the dinner, a surprisingly low total considering Obama’s vaunted fundraising ability during the 2008 election.

But the DCCC and DSCC fundraising coffers are certain to get a boost from a second fundraiser set for Friday and also taking place at the Mandarin Oriental hotel. The breakfast and briefing event, featuring Speaker Nancy Pelosi (D-Calif.), Senate Majority Leader Harry Reid (D-Nev.) and the chairmen of the two campaign committees is not subject to Obama’s lobbyist and PAC money restriction and the starting price for a ticket is $5,000.

Earlier Thursday, the National Republican Congressional Committee announced it brought in $3.24 million in May, while spending $3.2 million — a large portion of which went to paying off debt. The NRCC ended May with $3.7 million cash on hand and $4 million in debt.

The two Democratic committees and the NRSC had not released their May fundraising figures as of Thursday evening.