WASHINGTON — With John Roberts poised to win Senate approval as the 17th chief justice of the U.S. Supreme Court, Sen. Orrin Hatch took to the floor of the Senate on Tuesday to chide some Democrats for succumbing to special interest pressure to oppose the nomination.

"There are compelling reasons why the health of both the Senate and the judiciary require that this vote should be about, and only about, John Roberts' qualifications to serve as chief justice," said Hatch, R-Utah. "Some left-wing special interest groups seem to be urging a 'no' vote on this highly qualified nominee in large part to somehow send a message to President Bush as he deliberates on how to fill the remaining vacancy on the Supreme Court. If that is the case, it is a garbled, misguided message."

Because Roberts' confirmation is now assured — almost three-fourths of the 100-member Senate plan to overwhelmingly confirm him, Republicans on Tuesday began pressuring the Senate's minority Democrats to promise what they called a fair confirmation hearing and vote for President Bush's next Supreme Court nominee.

Bush could announce his choice to replace retiring Justice Sandra Day O'Connor as early as Thursday, the same day the senators plan to confirm Roberts.

But for now the Senate is focusing on Roberts, and Hatch, the ranking Republican on the Judiciary Committee behind Chairman Arlen Specter, R-Pa., said it is a political fact of life that political interest groups will demand to be heard. And there are Republican groups that would have wanted Republican senators to oppose President Clinton's nominees in similar fashion.

But that is not how the system works, Hatch said.

Hatch's comments appear to have riled Sen. Edward Kennedy, D-Mass., who was criticized in Hatch's floor speech for demanding a "litmus test" reflecting how Roberts would vote on controversial issues certain to come before the high court.

"Some of our friends on the other side of the aisle have tried to portray a vote against John Roberts as a reflexive, partisan vote against any nominee by President Bush," Kennedy said, not naming names but using Hatch's words almost verbatim. "Still others have made the sweeping statement that any senator who can't vote for Roberts can't vote for any nominee of a Republican president."

"These broad statements are patently wrong and suggest partisan posturing that does serious injustice to the most serious business of giving a lifetime appointment to a justice on the highest court in the land," he added.

It is a political reality, Hatch said, that whoever controls the White House has the right to nominate justices, and "in undertaking our advise and consent role, the Senate — due to the Constitution, prudence and tradition — owes a degree of deference to the president's nominees."