WASHINGTON » U.S. Sen. Daniel Inouye, the Senate's third-most senior Democrat, would assume the chairmanship of the powerful Appropriations Committee under a reported plan to replace Sen. Robert Byrd.

Byrd criticized Majority Leader Harry Reid yesterday over a news account that said Reid is plotting to oust him from his cherished post.

The inside-Washington newspaper Politico, citing anonymous sources, reported yesterday that Reid, D-Nev., is planning to ease Byrd, the longest-serving senator in history, from the helm of the powerful Appropriations panel and award the chairmanship to Inouye.

That provoked an unusually direct retort from Byrd, D-W.Va., who mentored Reid when the Nevada Democrat came to the Senate more than two decades ago. According to the Politico account, Reid has discussed the scenario with his advisers and with Inouye.

“;I am disappointed that, according to press accounts, the majority leader is talking to others about the chairmanship of the Senate Appropriations Committee,”; Byrd said in a statement released by his office. “;This is the sort of Washington back-room gossip which ill serves the Democratic Party in a year when Democratic unity should be paramount.”;

Inouye was on Molokai yesterday and unavailable for comment. In the Senate since 1963, he has served longer than anyone except Byrd and Ted Kennedy.

Last year, Reid had strongly defended Byrd, 90, after doubts about his capacity to lead the committee resulted in a spate of stories by Capitol Hill publications like Roll Call - also fueled by anonymous quotes from senators and their aides - speculating that he might be eased out.

In fact, those anonymous leaks to the media about Byrd had the probably unintended effect of shoring up support for him as senators felt compelled to make vows of loyalty, both privately and publicly.

Byrd is increasingly frail and usually relies on a script. He's taken to a wheelchair since a fall last year and other health problems led to several hospital stays. Top staff have served as surrogates in many negotiating sessions with top lawmakers.

The rumor mill is now churning again, and Reid's office is taking a more ambiguous stance in addressing them, noting that Byrd's future as chairman is up to fellow Democrats.

Reid spokesman Jim Manley said yesterday: “;Unless something changes, Senator Byrd will continue to be chairman of the Appropriations Committee.”;

Byrd has been campaigning in West Virginia for Barack Obama and for a former aide who's running for a U.S. House seat. He said he plans to help craft an economic stimulus measure when Congress reconvenes.