The conservative group Freedom’s Watch, headlined by two former senior White House officials, had been expected to be a deep-pocketed juggernaut in this year’s presidential election, heralded by supporters on the right as an aggressive counterweight to MoveOn.org, George Soros and the like.

But after a splashy debut last summer, in which it spent $15 million in a nationwide advertising blitz supporting President Bush’s troop escalation in Iraq, the group has been mostly quiet, beset by internal problems that have paralyzed it and raised questions about what kind of role, if any, it will actually play this fall.

The group was conspicuously absent this week as Gen. David H. Petraeus, the United States commander in Iraq, returned to Congress to testify. Moreover, the troubles at Freedom’s Watch come as some Democratic-aligned groups are seeking to take the offensive, with one group, Progressive Media USA, planning to raise $40 million to spend on advertisements and other efforts to undermine Senator John McCain of Arizona, the presumptive Republican nominee.

Independent groups not constrained by the limits placed on campaign contributions to candidates and parties have increasingly become major players in races for federal offices. Those known as 527s, named for the section in the tax code they fall under, raised more than $400 million in the 2004 election cycle alone, according to the Campaign Finance Institute. Such efforts could be especially beneficial for Mr. McCain, who has badly trailed his Democratic counterparts in fund-raising.