Updated

Trying to make up lost time, President Barack Obama plunged back into the search for money for his re-election campaign Wednesday with a coast-to-coast series of parties marking his 50th birthday after he was forced to cancel fundraisers because of the debt-ceiling crisis.

Lowering expectations, Obama's campaign said it would raise tens of millions of dollars less this summer than it did in the spring because it had to scrap 10 fundraisers headlined by Obama and others in California, New York and elsewhere and now faced a sluggish time of the year to raise campaign cash.

The campaign is looking to boost its summer fundraising, starting in Chicago, where Obama arrived Wednesday evening for three fundraising events. The president was greeted on his arrival by his former chief of staff, Rahm Emanuel, now mayor of Chicago.

Donors were paying between $50 and $35,800, the legal maximum, to hear Obama speak and watch local favorites Herbie Hancock, Jennifer Hudson and the band OK Go perform. Later, he was to attend a private dinner with about 100 high-dollar donors.

Obama also planned to speak via video conference to supporters gathered at more than 1,000 house parties around the country. The fundraisers come on the eve of the president's 50th birthday, and activists were being asked to recruit 50 new supporters to mark the milestone.

The president's quick stop in Chicago is his first trip outside of the Washington region in more than a month. His bruising tussle with congressional Republicans over raising the government's debt ceiling has kept him in the nation's capital and left little time this summer to prepare for a Republican challenger in 2012. His campaign juggernaut is expected to at least match the $750 million he raised in 2008 but has tried to tamp down those lofty expectations only weeks after reporting a combined $86 million between the campaign and the Democratic National Committee in the spring.

"We're going to raise significantly less in the third quarter than we did in the second quarter," said Jim Messina, Obama's campaign manager. "We will not be able to replace all of these events just because of his busy schedule. We always knew that he had his job and we had to do this around his schedule, and the truth is we just have to deal with canceling a month's worth of events."

The president still holds a large fundraising advantage over his GOP rivals and has been quietly building his campaign organization while Republicans try to establish themselves with voters in Iowa, New Hampshire and other early voting states. Former Massachusetts Gov. Mitt Romney collected more than $18 million through the end of June, while Minnesota Rep. Michele Bachmann, another top contender in the GOP race, brought in $4 million.

As part of Obama's birthday events, Democratic officials and campaign aides were fanning out across the country to raise money for Obama. The events included New York Gov. Andrew Cuomo in New York City, Obama campaign adviser David Axelrod in Los Angeles, DNC Chairwoman Debbie Wasserman Schultz in Washington, former White House press secretary Robert Gibbs and deputy campaign manager Jen O'Malley Dillon in Boston, and White House adviser David Plouffe in Tampa, Fla. Other events with Democratic surrogates were being held in Austin, Texas, and Oakland, Calif.

Democrats said the slow fundraising pace during the summer was expected because many donors are on vacation and high-dollar events don't typically resume until after Labor Day. Many donors, meanwhile, may not feel compelled to give money yet because the campaign is still in its formative stage and no clear Republican rival has emerged.

"This is not an easy time to raise money," said former Rep. Martin Frost, D-Texas, who led the House Democrats' fundraising arm. "His personal presence at events is important and he was tied up, certainly during the month of July, with the debt ceiling issue."

Republicans have called Obama the "campaigner-in-chief," and ripped his birthday fundraisers at a time of high unemployment and recent promises by Obama to reinvigorate a debate in Congress over how to boost the economy.

"He's tried all week now to play this spin that now the White House is pivoting to jobs, which they've tried many times before, and the first job the Obama is interested in saving is his own," said Republican National Committee Chairman Reince Priebus.

Obama last traveled outside the Washington region on June 30 for a fundraiser in Philadelphia. He is planning a jobs-oriented bus tour of the Midwest from Aug. 15-17 and expected to take a vacation later in the month. As a result, the campaign was expected to hold smaller gatherings headlined by Obama "surrogates," or high-profile supporters such as governors and lawmakers, during the summer.

Obama has experienced a summer lag in fundraising before. During his first presidential campaign, Obama raised about $21 million in the summer of 2007, compared with about $33 million in the spring of that year.

But now in the White House, Obama canceled two fundraisers in Southern California and events in Northern California, Seattle, New York and Washington, D.C., campaign officials said. Vice President Joe Biden skipped fundraisers in Atlanta, Nashville, Tenn., and Dallas, while White House chief of staff Bill Daley canceled an event in the nation's capital.

Only a few will be rescheduled. Obama's fundraiser in New York at the home of film mogul Harvey Weinstein is expected to be held later this month, while Biden's events are being rescheduled for the fall.