By Alan Elsner

WASHINGTON (Reuters) - Casting himself as a defender of democracy and the Constitution, Democrat Al Gore asked voters for patience on Monday while he contested the presidential vote in Florida, but Republican George W. Bush ignored his rival and plowed ahead with plans to take over the White House.

With polls showing his public support was falling, Vice President Gore appeared on TV for a five-minute address to explain why he was contesting Florida's official certification of Texas Gov. Bush as winner of its 25 electoral votes -- and therefore of the presidency.

``This is America. When votes are cast we count them. We don't arbitrarily set them aside because it's too difficult to count them,'' Gore declared, stating his position that there still had not been a fair and complete count in Florida, where Bush was declared the winner on Sunday by 537 votes.

``I believe our Constitution matters more than convenience. So, as provided under Florida law, I have decided to contest this inaccurate and incomplete count, in order to ensure the greatest possible credibility for the outcome,'' he added.

Accusing Republicans of intimidation to prevent a full count, Gore declared: ``A vote is not just a piece of paper. A vote is a human voice, a statement of human principle, and we must not let those voices be silenced.''

Republicans took to the airwaves to rip the vice president's appearance.

``It was nothing new. I don't think the vice president advanced his cause,'' said senior adviser Ari Fleischer.

``The vice president was spinning tonight; it wasn't statesmanship,'' Republican National Committee Chairman Jim Nicholson told CNN's ``Larry King Live.'' ``What's going on ... is that their base of support is eroding.''

Polls have shown around 60 percent of Americans, including around a third of Democrats, think it is now time for Gore to concede the election to Bush.

His appearance was clearly designed to shore up his base for the legal challenges he has launched in Florida.

Bush's strategy is to move ahead with his transition, headed by his vice presidential running mate Dick Cheney, while orchestrating maximum pressure on Gore to drop the struggle.

Republican sources said among Bush's first personnel announcements would be retired Gen. Colin Powell, almost certainly as secretary of state, and Condoleezza Rice in the post of White House National Security Adviser. But those announcements are not expected immediately while the legal battle still rages.

Gore said his fight was not personal but was a battle to defend a basic principle of democracy. ``Ignoring votes means ignoring democracy itself. And if we ignore the votes of thousands in Florida in this election, how can you or any American have confidence that your vote will not be ignored in a future election?'' he said.

Gore's lawyers challenged the Florida count in papers filed on Monday in Tallahassee, the Florida state capital, saying the tally improperly included illegal votes and excluded legal ones in Palm Beach, Miami-Dade and Nassau counties.

CONFUSING BUTTERFLY BALLOTS

In another development, the Florida Supreme Court said it would examine briefs relating to the so-called ``butterfly ballot'' used in Palm Beach County, which some voters said was confusing and may have led some Gore supporters to vote for conservative Pat Buchanan by mistake.

The court set a deadline of 5 p.m. Tuesday for submissions, after which it would decide whether to hear full arguments on whether the election should be rerun in the county.

The U.S. Supreme Court will hear arguments about the validity of hand recounts on Friday, which gives Gore a short window of opportunity to pursue his challenges. But he has to combat a growing sense of inevitability that Bush will become the next president on January 20, 2001.

News that the long-running U.S. presidential drama might be near its end sent blue-chip stocks to close higher on Monday.

Behaving very much like a president-elect, Bush claimed victory in the White House race late Sunday and asked Cheney to start working with the Clinton administration on the transition.

``It will be a while before we can make any announcements,'' Cheney said on Monday, although he noted that Bush had already had ``extensive conversations and discussions'' about potential Cabinet members.

Bush hit a stumbling block at the General Services Administration (GSA), which acts as landlord and building manager for the federal government. On Monday, it refused to turn over Washington office space set aside for a new presidency because of the legal challenges still going on.

Cheney said on Monday afternoon the Bush team would use private funds to set up a transition office in Washington, and would accept individual private donations of up to $5,000.

CHENEY REGRETS

Looking fit less than a week after suffering a slight heart attack, Cheney told a televised news conference that he found the GSA decision ``regrettable'' but added the Bush team felt obliged to start putting together the next administration.

He said Clay Johnson, a longtime Bush friend and aide, would be the executive director of the transition team, and campaign adviser and spokesman Ari Fleischer would be transition spokesman.

Bush got help on Capitol Hill, where Senate Majority Leader Trent Lott, a Republican of Mississippi, called on Monday for Senate committee chairmen to start hearings on Jan. 4 for Bush's Cabinet appointments.

``Given the protracted contest to determine the presidential victor, it is critical that we move expeditiously and be prepared to confirm the new cabinet on Jan. 20 after the president has been sworn into office,'' Lott said in a statement. The hearing date would be one day after the new Congress is sworn in.

With Bush the certified winner in Florida, 60 percent of 607 U.S. adults polled said Gore should concede and let Bush become president, an ABC News/Washington Post telephone survey found. Just 35 percent said Gore should ask the courts to review Florida's vote count. The poll's margin of error was 4 percentage points.