WASHINGTON — Charlie Spies knows how to raise money. The Republican lawyer helped rake in $153 million for Restore Our Future, the pro-Mitt Romney super PAC.
But he has had a harder slog with one of his latest projects, Republicans for Immigration Reform, a super PAC that aims to be a dominant force in the fight over revamping the country’s immigration laws. So far, the organization has made just a tiny ad buy in South Carolina and financed a poll with two other advocacy groups.
‘‘It has been a challenge to get donors on the Republican side to reengage,’’ Spies said.
Seven months after the 2012 election, a lingering hangover among conservative donors has stalled efforts by right-leaning independent groups to fill their coffers. Wealthy contributors who dashed off six- and seven-figure checks last year are eying super PACs and other politically active groups more skeptically, frustrated that the hundreds of millions of dollars spent to elect Romney was for naught.
‘‘There’s donor fatigue,’’ said Fred Malek, a GOP operative wired into high-net-worth circles. ‘‘Everyone was in a frenzy of giving up until the November elections, and then everyone was sort of worn out on the whole process. It’s very hard to raise money after an election, especially after you lose.’’
Several Republican fund-raisers said they remain optimistic that the money spigot will reopen as the 2014 congressional elections approach. But this time around, donors are seeking to be more judicious about where they put their money, asking groups for detailed strategy and spending plans.
‘‘At the moment, I’m kind of in a waiting and watching mode,’’ said Howard Leach, an ambassador to France under President George W. Bush. In 2012, Leach gave $100,000 each to Restore Our Future and American Crossroads, the conservative super PAC cofounded by former Bush political strategist Karl Rove.
Post-election donor apathy is not limited to the political right. Organizing for Action, a nonprofit group launched by former advisers to President Obama to back his agenda, has halved a $50 million fund-raising goal for its first year after slower-than-expected fund-raising, according to people familiar with the group’s plans.
The decision came after the group reversed course and said it would not accept corporate funds.
But the pressure to bring in big checks is greater for pro-Republican groups, which have not been able to match the extensive small-donor network that was built by Obama’s campaign and that OFA is now drawing on. There are signs that donor reticence stems in part from dissatisfaction with the uneven track record of super PACs and opaque nonprofit groups, which can raise unlimited funds.
Many top contributors are now questioning the value of financing such organizations, which operate independently of candidates and party leaders.
Frank VanderSloot, chief executive of an Idaho company who gave abundantly to Romney and groups backing him, said he has concluded that it is not effective to finance tax-exempt advocacy groups that can spend only a limited amount on politics.