Washington ? Senate supporters of landmark immigration legislation looked ahead Wednesday to passage of a measure along lines set by President Bush, but they also signaled a willingness to seek common ground with conservatives whose House version would be far tougher on millions of men and women in the country illegally.

With Senate approval assured today, Arlen Specter, R-Pa., the chairman of the Judiciary Committee, said: “Does anybody have a better approach? Not yet. But we’re still open for business.”

“If there are some unneeded and unwanted complexities in this legislation, they could probably be smoothed out,” said Sen. John McCain, R-Ariz. He said it was good news that new suggestions were coming from the House.

The Senate bill’s passage, long assumed, was assured with a decision to limit debate. That 73-25 vote set the stage for final approval today in what will be a bipartisan ratification of legislation that calls for increased border security, a new guest worker program and a shot at citizenship for millions of illegal immigrants.

By contrast, legislation passed last year by the Republican-controlled House is generally limited to border security. It would expose all of the estimated 11 million to 12 million illegal immigrants in the country to felony charges, and it contains no guest worker program.

Numerous conservative House Republicans have denounced the Senate measure as conferring amnesty on lawbreakers. Some have demanded that House leaders refuse to enter compromise discussions with the Senate, and they have warned that giving too much ground could cause conservatives to stay home this November and spell defeat for the party in midterm elections.