WASHINGTON (AP) – Michael K. Powell has tackled thorny issues involving media ownership rules, phone competition and the Internet as the nation’s top communications regulator, but a “wardrobe malfunction” got him the most attention.

Powell announced Friday that he will step down in March as chairman of the Federal Communications Commission, culminating a four-year tenure in which the Republican-controlled agency championed a generally pro-business agenda and dramatically stepped up enforcement of broadcast indecency standards.

Powell’s departure had been expected, though the timing was a surprise. In an interview, Powell said he reached his decision over the holidays and looked forward to vacationing with his wife and two sons, aged 16 and 10.

Powell may be best known by the public because of the FCC’s harsh response to Janet Jackson’s “wardrobe malfunction” during last year’s Super Bowl halftime show. But Powell said he’s proud of his efforts to promote new technologies like high-speed Internet access and digital TVs.

“Our principal passion is that we believed we should work hard to get the law right to stimulate innovative technologies that put more power into the hands of consumers,” said Powell, son of Secretary of State Colin Powell, who also is leaving his job. “I felt very comfortable that we achieved most of what we set out to do.”

White House spokeswoman Erin Healy praised Powell for a “strong commitment to expand the reach of new communications technologies and services” that promoted President Bush’s goal of affordable high-speed Internet access for all Americans by 2007.

Though he clashed often with the two Democrats on the FCC, all five commissioners have been united in seeking harsher penalties for violations of broadcast indecency standards.

The FCC received more than 1 million indecency complaints in 2004, most of them involving the exposure of Jackson’s breast during her performance. Fines for indecent programming exceeded $7.7 million last year, a huge increase from the $48,000 imposed the year before Powell became chairman.

As a result, programmers have become more skittish about what may or may not be construed as too racy. Some networks have started using a broadcast delay on live programs to catch any offensive material before it aired. Last year, 66 ABC affiliates decided not to air the movie “Saving Private Ryan” on Veterans Day over similar fears.

Critics of the FCC’s crackdown, from academics to shock jock Howard Stern, accuse Powell and the FCC of stifling free speech. Stern, who has accumulated more fines than anyone else, decided to switch next year to satellite radio, which is not subject to the indecency standards because listeners pay for the service.

Paul Levinson, chair of the Communication and Media Studies Department at Fordham University and a frequent Powell critic, said the indecency crackdown is misguided.

“What we need is an FCC to go to Congress and tell them that First Amendment rights are there to protect what people don’t like,” Levinson said.

Powell said the FCC’s stepped-up enforcement was in response to growing complaints from the public and lawmakers that broadcasts had become too raunchy.

Lara Mahaney, spokeswoman for the Parents Television Council, which frequently complains about sex and violence on television, said Powell should have acted long before the Janet Jackson incident.

“In regards to indecency, we give him an F,” Mahaney said of Powell.

The FCC has five members, and the party in power at the White House holds three seats. Powell was nominated by former President Clinton to a Republican spot on the then-Democratic dominated commission in 1997. Bush made him chairman in 2001.

Among other controversial issues Powell tackled as chairman was a revision of decades-old rules governing ownership of newspapers and television and radio stations. The commission approved changes in 2003 that allow individual companies to own TV stations reaching nearly half the nation’s viewers and combinations of newspapers and broadcast outlets in the same community.

The changes were favored by major media companies, but Congress and the courts are considering several efforts to modify or repeal the rules.

Last month, the commission made yet another attempt to promote local phone competition. Three previous efforts have been thrown out by federal courts.

There was no immediate word on a successor. Possible replacements include Republican Commissioner Kevin Martin, who would not need Senate confirmation to become chairman because he already is on the FCC.

An aide to Sen. Ted Stevens, R-Alaska, chairman of the Senate Commerce Committee, said Stevens has recommended to Bush that a former Stevens adviser, Washington attorney Earl Comstock, be nominated to the commission. But Stevens’ office said there have been no discussions with the White House about who should assume the chairmanship.

Other names being mentioned include former Texas utilities regulator Rebecca Armendariz Klein and former chairman of the Federal Energy Regulatory Commission Pat Wood.