WASHINGTON, D.C. -- Sen. Joseph Lieberman's friends are certain that if Democrats expand their one-vote Senate edge in this year's elections, they will kick him out of the Senate Democratic caucus and, therefore, oust him as Homeland Security Committee chairman.

Lieberman risked the usual punishment of ejection from the party caucus when he endorsed Republican Sen. John McCain for president and actively campaigned for him. But with Democrats in a Senate majority of only 51 to 49, they would lose control if Lieberman defected to the Republicans.

After being defeated by an anti-Iraq war candidate in the 2006 Connecticut Democratic primary, Lieberman kept his Senate seat in the general election by running as an independent and now calls himself an "Independent Democrat." He became Homeland Security chairman under the Democrats' strict seniority rules by remaining in the party caucus. Despite his participation in McCain's campaign, Lieberman generally votes the straight Democratic line on issues other than Iraq.

ROMNEY FOR VP

Mitt Romney has pleased John McCain with his help since losing the Republican presidential nomination, but it remains unlikely the former Massachusetts governor will be selected for vice president.

Former Gov. Jeb Bush is reported by Florida Republican insiders as favoring a McCain-Romney ticket, added to backing from former White House political chief Karl Rove and some senior McCain campaign staffers. Nevertheless, the McCain consensus is that defects that made Romney a problematic presidential candidate also would hurt him as a running mate.

A footnote: Minnesota Gov. Tim Pawlenty gets higher marks from the McCain inner circle than from conservative Republican governors and is in the running for vice president.

PETRAEUS TO NATO?

Persistent rumors that Gen. David Petraeus will be transferred from his Iraq command to NATO are attributed by Pentagon sources to his critics in the Army officer corps.

These sources consider it unlikely that President Bush, entering his final months in office, would shift Petraeus from the Army's most important military command to a relative backwater. Such an assignment is desired by fellow general officers, who resent Petraeus for outstripping his senior colleagues.

A footnote: One of Petraeus' friends in the officer corps suggests the best thing Bush could do for him now would be to permit his wife to move from the United States to Jordan for the remainder of his Iraqi command.

BUSINESS FLINCHES

The national business lobbies that have pushed hard for congressional approval of the Colombian Free Trade Agreement flinched when asked to help defeat House Speaker Nancy Pelosi's unprecedented pre-emptive strike.

Pelosi moved to change the rules so the House would not have to vote on a trade pact that is opposed by organized labor and has been pushed by President Bush. When asked to join in trying to block Pelosi's move, Washington's top business lobbyists declined. Without business opposition, Pelosi prevailed in the House Thursday 224 to 195 on a largely party-line vote.

The lobbies explained they do not like to get involved in a procedural vote, as this would be. The real reason, however, may be unwillingness to confront Pelosi, who will still be around when Bush is gone.

MCCAIN'S LIBERAL

John McCain's presidential campaign has made clear to conservatives that liberal Republican Bobbie Greene Kilberg will not be running the party's national convention in St. Paul, Minn., this summer, as this column indicated March 22.

My sources had informed me that Kilberg, a longtime McCain supporter, definitely had been decided on as convention manager. This column's report created a firestorm of complaints from conservative activists and many McCain backers. The McCain campaign immediately responded that Kilberg was merely McCain's "liaison" with the Republican National Committee (RNC).

Since then, a McCain spokesman has downgraded Kilberg to "good friend" without a top staff position. RNC staffer Maria Cino is handling details of the St. Paul convention with an overall manager yet to be named by McCain.