Since the Senate last confirmed a Supreme Court justice, more than half of its seats have changed hands. Only three senators remain, all Democrats, who took part in all of the highly charged, conservative-liberal confirmation battles since 1968.

And a mythology has sprung up over how much the 1987 defeat of conservative Robert Bork changed the role of outside interest groups in fights once waged solely in Senate halls and chambers, a longtime Senate aide says.

“All of that is history written by people who weren’t there,” said James Flug, then as now a close adviser to Democratic Sen. Edward Kennedy. He said some of the same liberal groups have always been involved, though he conceded the cast on the conservative side has changed and grown since Bork’s rejection.

To a considerable degree, the battles have all been similar, revolving around two conflicting concepts of the courts. In the 1960s and 1970s, conservatives complained of activist positions on political and criminal issues, like reapportionment and criminal rights; now, they dispute efforts to set policy on social issues like abortion and gay marriage.

But Flug acknowledged other factors have altered the nature of confirmation fights – the Senate’s changing makeup, revisions in its rules and a decreased emphasis on the substance of judicial issues. The result: greater acrimony and partisanship.

The veteran Washington attorney, who returned to the Massachusetts Democrat’s staff two years ago after 30 years in private practice, compared today’s Senate with the one that, in the late 1960s and early 1970s, blocked three Supreme Court nominees, a liberal and two conservatives.

In 1968, Republicans and conservative Democrats rebuffed President Lyndon Johnson’s effort to install longtime adviser Abe Fortas as chief justice. After Richard Nixon won the White House, Democrats led battles that rejected Judges Clement Haynsworth and G. Harrold Carswell.

Flug cited these differences:

Senate divisions, once on ideological lines that spanned both parties, now fall mostly along party lines. Democrats have lost a majority that was always greater numerically than ideologically.

In November 1969, 17 Republicans joined 38 Democrats in rejecting Judge Haynsworth, including the two top GOP leaders.

Later, 13 Republicans helped 38 Democrats beat Judge Carswell. “In both votes, the Republicans made the difference,” he said.

Back then, it took 67 votes to limit debate, rather than today’s 60. “So you needed even more for a consensus to get anything through,” Flug noted.

There was less party discipline so supporters and foes of the nominees ran the fight, not the party leaders. “You couldn’t count the votes in advance,” he said. “You had to make your best estimate of what was possible.”

Debate centered on the nominees’ substantive positions. “No one paid much attention to the voting until you got to the end because there was no party discipline,” he said.

As for outside groups, Flug noted that, on the liberal side, two main players remain the same: organized labor and the Leadership Conference on Civil Rights. But he conceded that far more conservative groups have become active since Bork’s rejection.

“But the idea that the groups are driving the thing, at least on our side, is not true,” he said.

Though there was nothing then like the Internet and today’s cable news networks, Mr. Flug noted there was intense media coverage.

“In Washington, you still had three local papers, and the afternoon papers put out several editions,” he said. “And the wire services were putting out stuff all the time, and it went to the radio stations that had hourly newscasts.

“So to some extent, I think it’s a bit exaggerated that it’s so much of a difference,” he said.

Despite today’s greater partisanship, Flug said, some senators on both sides agree “consultation and consensus would be a lot better for everyone than confrontation and conflict.” That was clear in the bipartisan effort by 14 senators to head off a GOP leadership effort to change the filibuster rule.

Flug noted that Bush faces a similar choice to one Nixon faced after the Senate rejected Judge Haynsworth over conflict-of-interest charges.

Without consulting senators, Nixon picked an even more conservative nominee the second time – and lost again.