• Exit part of sweeping change in US surveillance leadership • Move comes just days after Rogers introduced NSA reform bill

The National Security Agency’s most stalwart congressional ally is abruptly retiring, part of an almost complete turnover in surveillance leadership less than a year after Edward Snowden’s revelations ushered the spy agency into a new and uncertain era.

Congressman Mike Rogers of Michigan, the powerful chairman of the House intelligence committee and a former FBI agent, announced on Friday morning that he is leaving Congress at the end of his term to start a conservative talk radio show.

“It's a pretty rare opportunity. They don't come around very often,” Rogers, a Republican, told a Detroit-area radio show.

The surprise move comes four days after Rogers introduced a bill that would significantly constrain the NSA’s bulk collection of US phone data, a policy Rogers said he came to reluctantly after recognizing the lack of public and congressional confidence in the most domestically controversial of surveillance programs exposed by Snowden through the Guardian.

Rogers’s bill, however, provides fewer judicial obstacles to the government’s continued acquisition and search of phone and email data than does a competing proposal from members of the Senate and House judiciary committees and a new offering to end bulk data collection from the Obama administration.

Supporters of the latter proposals believe their efforts have been made tougher after the House parliamentarian, allegedly at the behest of the House speaker, John Boehner, gave the intelligence committee primary jurisdiction of Rogers’ bill on Thursday. Some House aides suspect the move is a prelude to a quick floor vote on the measure. But that was before Rogers announced his retirement, adding an unexpected element to the legislative competition.

Rogers is a close ally of Boehner, who will determine the next chairman of the committee, a largely secret panel that serves as the chamber’s proxy on intelligence oversight. A possible successor, should the GOP hold the House in November as expected, is Texas Republican Mac Thornberry, another legislator deeply interested in intelligence and cybersecurity issues, although Thornberry is a likely favorite to take the gavel of the House armed services committee instead.

A spokesperson for Rogers did not immediately return a request for comment.

Rogers’ departure from Congress is part of a near-wholesale replacement of leadership in the NSA and its chief allies in the other branches of government.

Keith Alexander: also retiring. Photograph: Fang Zhe/Xinhua Press/Corbis

On Friday afternoon, General Keith Alexander, the longest serving director in the NSA’s history, will formally retire from the army. His replacement, Vice Admiral Michael Rogers – no relation to the congressman – was ratified by the Senate armed services committee on Thursday for a related job atop the military’s Cyber Command, a prelude to an imminent, expected confirmation before the full Senate.

Rogers’ civilian deputy, Rick Ledgett, took office just after the new year.

In May, Judge Thomas Hogan, a Ronald Reagan appointee, will become the presiding judge of the secret Fisa court, the main judicial step for approval of ostensibly foreign-focused government surveillance. Hogan, who has sat on the Fisa court for years, was the choice of chief justice John Roberts.

The nominal chief of US intelligence, James Clapper, the director of national intelligence, has not announced any plans to leave the administration. Now in his fourth year in office, Clapper’s reputation has taken a hit after Snowden’s revelations that the government secretly collects all US phone records gave the lie to his March 2013 Senate testimony that the government does “not wittingly” vacuum up records on millions of Americans.

Director of national intelligence James Clapper has taken a hit – but he has not announced plans to leave. Photograph: Pablo Martinez Monsivais/AP

Rogers, a constant presence on news shows, has become the NSA’s senior public proxy for character attacks on Snowden, usually without providing evidence. At a Tuesday press conference, Rogers – who largely referred to Snowden simply as “the former contractor” – issued several accusations based on his description of a secret Defense Intelligence Agency report.

“At least those analysts believe that information, some or all of it, would be in the hands of the Russian intelligence services today. The question on this is not whether he is under the influence of the Russian intelligence services today, everybody agrees on that, the question is when did that start,” Rogers said.

Rogers further alleged, also without evidence, that Snowden’s revelations of widespread NSA bulk surveillance worldwide was “deadly to our military,” although no US servicemember or any other person’s death or injury has been linked to the NSA disclosures.

“I think the media got a little confused that it got everything he had. I am here to tell you that is not true, they didn’t get hardly anything that he stole,” continued Rogers, who is reliant on an intelligence apparatus that is still guessing at the extent of the Snowden leaks.

When asked if the intelligence committee even knew how many more NSA disclosures were yet to come, Rogers’ chief Democratic ally on the committee, Dutch Ruppersberger of Maryland, quipped: “The Guardian will take care of that.”

It is extremely rare for the chairman of one of the national-security related committees in Congress to decamp for a job in the media. One of Rogers’ most recent predecessors, Republican Porter Goss of Florida, cut his tenure on the intelligence committee short in 2004 to become CIA director.

Rogers thanked supporters in a statement announcing his retirement.

“As I close this chapter please know that I am not finished with the effort to bring back American exceptionalism,” Rogers said.

“Not in the sense of a great notion, but in the sense of impacting the hopes and dreams of a great nation and her people. You may have lost my vote in Congress, but not my voice. I look forward to building on our successes and confronting America’s challenges together.”