Mitt Romney, Haley Barbour and Newt Gingrich aren’t the only people who are doing everything to prepare for 2012 presidential runs without actually declaring they’re candidates.

President Obama, who has not said officially he will run for a second term but is virtually certain to, is quietly starting to engage personally in his reelection effort. On Wednesday night, for the second time this week, Obama met with major Democratic donors at a Washington hotel.

The event was not a fundraiser but was instead a way for Obama to greet and talk to longtime donors on the Democratic National Committee’s finance committee and advisory board. He made a similar appearance earlier this month in Miami.

Obama has also been meeting with groups of college students on his recent stops across the country, an effort the White House says is not political but seems designed to fire up a key part of the president’s base, people under 30.

In his speech Wednesday to about 500 donors, Obama hinted at what will be a major challenge for his campaign: rekindling the energy from both donors and grass-roots activists that helped him win in 2008.

“My hope is that the same spirit that helped change this country in 2008, that that spirit is still in each and every one of you,” he said. “Obviously the first time around it’s like lightning in a bottle. There’s something special about it, because you’re defying the odds. And as time passes, you start taking it for granted that a guy named Barack Hussein Obama is president of the United States.”

He added, “we should never take it for granted. And I hope that over the next couple of years, as we’re seeing a lot of you as I travel around the country, I hope that all of you still feel that sense of excitement and that sense of possibility, because we still have so much more to do.”

Much of the speech mirrored the remarks Obama frequently delivers in public on education, innovation, the economy and his other priorities. But he directly addressed one frequent critique of Democratic Party activists: He isn’t eager enough to directly take on the GOP.

“I know that sometimes people may get frustrated and think, you know what, Obama is being too nice and we need to get in there and take it to them,” he said, as the crowd laughed. “And there will be times where that’s important. But I also think it’s important for us not to lose that spirit that animated us early on, which was to say that we don’t want to just fight the same old battles over and over again.”

Obama, of course, hopes that energy and excitement will translate into money. The president’s 2008 campaign was aided by a huge fundraising advantage over Sen. John McCain (R-Ariz). But it’s not yet clear Democrats will be as excited or as motivated in 2012.

Obama today

The president will celebrate St. Patrick Day’s by hosting Irish Prime Minister Enda Kenny at the White House for a meeting and an evening reception, as well as joining Kenny for a lunch on Capitol Hill.