Bush met with separate groups of 15 mostly moderate Republican and Democratic House members.
According to participants, Bush said the new secretary should be allowed to "transfer" employees from their positions. And he pressed for the right to waive collective bargaining rules for national security purposes, saying such rules already apply to existing agencies.
New York GOP Reps. Jack Quinn and Peter King each said afterward Bush had gained some converts, at least among GOP legislators.
"In time of war, when the president makes a national security argument, he's inclined to get the benefit of the doubt," said King, who added he would support Bush.
According to King, civil service provisions in the bill approved by the Homeland Security Committee last week "are being worked on" to make them "more palatable to the unions."
But Bush is seeking defeat of an amendment by Rep. Constance Morella, R-Md., to grant homeland security workers stronger protections, King said.
Bush emphasized that department employees still would have protections under existing civil rights laws, the Fair Labor Standards Act and the Social Security Act, as well as whistleblower protections, a participant said.
Though he did not specifically threaten a veto, sources said Bush termed a "nonstarter" any move to make the White House Office of Homeland Security a confirmable position.
One White House official indicated Bush aides are drawing up invitation lists for the meetings to target lawmakers who might be under union pressure to buck the president on this issue but who could be "gettable" nonetheless.
Among those at a Democratic session were Reps. Calvin Dooley, Ellen Tauscher and Jane Harman of California, Chris John of Louisiana and Sanford Bishop of Georgia.
In response to his pitch to Republicans, Bush was forced to field at least one ground ball.
According to participants, Rep. Jim Greenwood, R-Pa., tongue most likely in cheek, said he was close to supporting the president but that he needed a favor.
He then rolled a baseball down the Cabinet room table toward Bush and asked for it to be upgraded for his son with a presidential autograph.
Bush quickly signed.