But for every line of inquiry that led to a public hearing or legislation, administration supporters and critics alike complain privately — White House and agency officials especially fear upsetting the chairman — that many of the efforts by Issa’s staff resulted in no follow-ups, no hearings or no reports. Essentially, some complain, there have been too many instances in which there was more show than substance.

Eric Schultz, a White House spokesman hired last year to handle the crush of media requests anticipated by GOP oversight investigations, puts it delicately.

The White House has cooperated “with legitimate congressional requests for information,” he said. But “we believe that neither political motivations nor political theater should drive congressional oversight.”

Issa issued 22 subpoenas and published 11 investigative GOP staff reports, and the panel sent 748 letters seeking information from the White House and federal agencies in his first year, according to the panel’s records.

Some Issa hearings have had their share of drama. Last week, Democrats walked out of a session when Issa blocked testimony from a woman who supported the Obama administration’s decision to require insurance companies to pay for the contraceptives of employees at faith-based institutions that object to them. Issa said the Georgetown University law school student did not have the appropriate credentials to testify at a hearing regarding perceived threats to religious freedom.

One issue, however, that has earned the chairman and his panel bipartisan kudos — and significant headlines — is the Department of Justice’s “Operation Fast and Furious” gun debacle.

Whether he strikes an administration nerve or not, Issa isn’t apologetic for his aggressive style.

“Do we send a lot of letters out? Yes,” he said recently. “When we hear about it, we send letters. And when we get answers, we very quickly say, ‘We’re all set, thank you very much, we’re done.’ ”

In addition, Issa and his aides noted that the administration faced virtually no serious congressional oversight in its first two years, when Congress was controlled by Democrats.

Administration officials provided a list of dozens of oversight panel requests that appear to have fallen flat. The committee sought information on the White House’s ties to Google after a former company official who had joined the administration used his personal Gmail account to e-mail former colleagues. Republican committee staffers later pressed federal agencies to detail how quickly officials granted Freedom of Information Act requests. Issa also inquired about President Obama’s meetings with political advisers and about why Federal Communications Commission Chairman Julius Genachowski visited the White House so frequently.