WASHINGTON (Reuters) - U.S. Senate Democrats on Tuesday blocked a seventh Bush administration judicial nominee, reigniting a partisan battle certain to intensify as the November elections near.

On a largely party-line vote of 53-44, Republicans fell seven short of the needed 60 to clear a procedural hurdle against President Bush's nomination of William Myers to the federal bench.

Bush wants to put Myers, a former top lawyer at the U.S. Interior Department who also worked as an industry lobbyist, on 9th U.S. Circuit Court of Appeals in San Francisco.

During a spirited debate on Myers, now a private attorney in Boise, Idaho, Democrats and Republicans exchanged what have become dueling campaign refrains.

Republicans accused Democrats of obstructionism, and Democrats accused Bush of trying to line the federal courts with right-wing ideologues.

"The prejudices against Bill Myers reflect today's poisoned confirmation process," said Judiciary Committee Chairman Orrin Hatch, a Utah Republican. "Nominees who somehow offend any well-funded liberal interest group are subject to distortions and baseless personal attacks."

But Sen. Patrick Leahy of Vermont, the committee's top Democrat, said: "William Myers epitomizes the anti-environmental tilt of so many Bush nominees. He should not be confirmed."

While Republicans hailed Myers as an able lawyer, Democrats denounced him as a tool of industry and a threat to the environment.

Myers became the first judicial nominee to be blocked since a temporary truce was reached in May between Senate Democrats and the White House.

Democrats permitted confirmation votes on 25 other nominees for lifetime appointments in an exchange for Bush's promise to stop seating judges while the Senate is on recess.

That promise is good through the remainder of Bush's current term, which ends in January. Early this year, Bush made two temporary recess appointments of appeals court nominees who had been previously blocked by Senate Democrats.

Democrats said they have tried to cooperate on judicial nominees, noting they had helped Republicans confirm about 200 of Bush's acceptable judicial candidates.

There are now about two dozen judicial nominees pending, and it is uncertain how many the Senate will confirm before this Congress comes to an end in January.

With concerns that many will be left hanging, Republicans are considering making a big push for confirmation before Election Day, said Sen. John Cornyn, a Texas Republican.

"You'll see a rather high-profile effort to try to get as many confirmed as possible," Cornyn said.