WASHINGTON (AP) ― Mitt Romney and the Republican Party surged ahead of President Barack Obama in fundraising for the first time Thursday, a key development at a time when many liberals among the Democrats have become frustrated with the president.

Romney and his party raised more than $76 million in May, the campaign said, while Obama’s campaign reported it and the Democratic Party raised $60 million for the month. That’s a significant increase for Romney: He and the Republicans brought in $40 million in April ― short of the $43.6 million that Obama and his party raised that month. 

The fundraising numbers signal a new stage in the campaign as Romney capitalizes on his emergence as the party’s standard-bearer and as Obama is forced to confront the political implications of a weak economic recovery and increasing frustration among Democratic Party liberals.

Many of the some 2,700 participants Thursday at Netroots Nation ― described by the annual convention as “a giant family reunion for the left” ― believe Obama has not fought hard enough for progressive priorities on taxes, health care and the economy.

With the election just five months away, some are threatening not to donate money or time or even vote in November for the man who ignited their passions and captured their imaginations four years ago.

“I want to be happy with him,” said Democrat Kristine Vaughan, a 45-year-old school psychologist. “But I am finding that he has succumbed to the corporate influence as much as everyone else.”

Polls show the president locked in a tight race that’s likely to be decided in several swing states where he scored narrow victories four years ago. States including Ohio, Florida and Virginia are expected to be very competitive, and Obama needs liberal supporters to aid the campaign and turn out in droves on Election Day.

Besides topping Obama in May fundraising, Romney is getting a significant boost from Republican-leaning super political action committees that have raised far more and spent far more than their Democratic-leaning counterparts.

Romney, campaigning Thursday in Missouri, stepped up his criticism of Obama in a speech at a factory in St. Louis. He accused Obama not only of a failure of policy, but of “a moral failure of tragic proportions.”

Citing millions of unemployed or underemployed Americans, Romney said Obama nevertheless claimed he was doing a great job. “I will not be that president of doubt and deception,” he said.

More than a dozen liberals interviewed at the three-day Netroots Nation convention indicated some level of frustration with the president, despite widespread praise for his recent decision to support gay marriage and ongoing push to scale back military action in the Middle East.

Most said they plan on voting for Obama and their gripes are not unlike what the White House has heard for much of the president’s term. But these left-leaning backers’ varying levels of enthusiasm could spell trouble for a president whose 2008 victory was fueled by a massive network of grass-roots volunteers and small-dollar donors.

“I look forward to him fighting much harder,” said Arshad Hasan, executive director of Democracy for America, a group founded by former Vermont Gov. Howard Dean.

Despite the criticism, polling suggests Republicans may face a larger enthusiasm gap than Democrats.

In late May, a Washington Post-ABC News poll found that 93 percent of Obama voters said they are enthusiastic about voting for him, including 51 percent who were very enthusiastic. For Romney supporters, 75 percent were enthusiastic, and just 26 percent were very enthusiastic.