With enemies like these, who needs friends?

Senator Bernie Sanders often boasts that he has no “super PAC” supporting his candidacy and he has vigorously tried to keep any from forming. But he has been getting some unsolicited if mischievous help from Republican groups actively promoting the Vermont senator’s surging campaign.

America Rising, a Republican political action committee, reacted with glee on social media on Tuesday to a CNN/WMUR poll that showed Mr. Sanders with a large lead over Mrs. Clinton in New Hampshire, sharing the news with “BREAKING” qualifiers and links to news stories.

Karl Rove’s American Crossroads recently created an ad parroting Senator Bernie Sanders’s critiques of Mrs. Clinton’s ties to Wall Street, made repeatedly last week in the days before Sunday’s debate.

And during the debate, Republican groups were blasting out rapid emails defending Mr. Sanders’s positions, including his universal health care plan, an issue many Republicans would embrace as warmly as they would higher taxes.

All of it, of course, is intended to get under Mrs. Clinton’s skin and promote the Democratic candidate they believe would be weaker in a general election. Republican groups and super PACs have spent nearly $5 million targeting Mrs. Clinton so far this cycle. They’ve yet to spend a dollar on advertising attacking Mr. Sanders.

The Clinton campaign released a statement saying this support only furthers their argument that Mrs. Clinton is the candidate the Republicans are most afraid of facing.

“The Sanders argument falls apart when the G.O.P. spokesman is trying to help him and the Republicans run ads trying to stop Hillary Clinton in the primary,” said Jennifer Palmieri, the communications director for the Clinton campaign, in a statement. She asserted that Mr. Sanders was “taking his cues” from Mr. Rove, though the senator’s Wall Street attacks predated the Rove ad.

The effort on the right to attack Mrs. Clinton from the left has actually been underway for a while, with groups like American Crossroads and America Rising targeting digital content criticizing Mrs. Clinton’s positions on the Keystone oil pipeline, for example.

“The idea is to make her life difficult in the primary,” Colin Reed, America Rising’s executive director, said last year.