The annual Congressional Hispanic Caucus dinner is a regular stop on the Washington dinner circuit. But it wasn't until this year that first lady Hillary Rodham Clinton decided to go.

Now that she's running for the Senate, Clinton took center stage at the Washington gala last night to woo 1,500 Latino activists. Vice President Gore, focusing on his campaign for president, shared the spotlight, and delivered a kiss on each cheek to the first lady.

Gore's leading Republican rival, Texas Gov. George W. Bush, spent last night celebrating Mexican independence from Spain at a traditional Dieciseis de Septiembre (16th of September) party in Detroit.

And over at the Republican National Committee, officials are finalizing plans to run the first-in-a-decade television ads targeting Latino voters.

As the 2000 campaign gets underway, politicians of every stripe--at every level--are rushing to win over the increasingly influential Hispanic vote.

"If a candidate wants to divide this nation instead of uniting us, if a candidate speaks the rhetoric of inclusion but pursues policies of exclusion, then that candidate is going to pay at the ballot box," Gore told the crowd at the Hispanic dinner. "You will make sure of that."

The reason for all the attention is simple math. New census data released yesterday show the Hispanic population increased by more than 35 percent in the 1990s. By the end of 2004, census counters project, Latinos will be the largest minority group in the nation.

More importantly to the politicians, Latinos vote, and with their numbers climbing and their willingness to cross party lines, Hispanics could tip the scales in critical races next year.

In the last presidential election, 18.5 million Hispanics voted, accounting for 5 percent of the total turnout, according to Hispanas Organized for Political Equality (HOPE), a nonpartisan organization formed to promote Hispanic participation in government. In national elections, their clout is magnified because it is concentrated in five electorally rich states: California, Texas, Florida, New York and Illinois.

"From New York to California, I have met Hispanic leaders and citizens who have been and now are attaining what they demanded--a seat at the table and an opportunity to chart their own destiny," said Hillary Clinton.

This week, kicking off Hispanic Heritage Month, several large Hispanic political organizations convened in Washington to lobby leaders of both parties. On Tuesday, Gore collected the endorsements of 521 Hispanic state and local officials, as well as members of Congress. "Lo accepto"--I accept--a beaming Gore said at a boisterous rally. Today he plans to address the Hispanic Chamber of Commerce in San Diego.

"I tell my colleagues, 'If you're not opening your eyes to this demographic group you're going to fail miserably,' " said Rep. Henry Bonilla (R-Tex.), who is helping Bush pursue the Latino vote nationwide.

Bush, who recently gave a major education speech at a meeting of the California-based Latin Business Association, is scheduled next week to attend the Republican National Hispanic Association in Washington.

Republican Sen. John McCain, who has consistently drawn a solid bloc of Hispanic votes in his home state or Arizona, also has begun a series of breakfast meetings with Latino leaders around the country, said aides.

Compared to four years ago, when Latinos felt neglected if not outright offended by Republican Robert J. Dole and his support for a range of anti-immigrant initiatives, it appears Hispanics will be courted by the GOP in 2000, said Lisa Navarrete, spokeswoman for the National Council of La Raza, the nation's largest Latino advocacy organization.

"Almost regardless of who gets the nomination in either party, the Latino vote is being sought after quite aggressively," she said. "That's a dramatic difference from 1996."

Both Gore and the first lady attacked the proposed Republican tax cut plan, saying it would decimate educational and health care programs that especially benefit Latino children. Speaking in Spanish, Gore promised the president would veto the bill with the simple message: "My signature? Not today. Not tomorrow. Never."

But tensions remain. Hillary Clinton angered Puerto Rican leaders when she announced she opposed President Clinton's clemency offer to members of a violent independence movement known as FALN. Yesterday, she tried to bandage those wounds in an appearance with Bronx Borough President Fernando Ferrer.

"We have so many common goals," she said during an afternoon news conference in New York. "There will be disagreements. I think, though, they pale in comparison to what we can do on behalf of the people in this city . . . and I look forward to working with Freddy and everyone here."

California Assembly Speaker Antonio Villaraigosa said in an interview that Hillary Clinton "mishandled the response . . . it was a gaffe." But he said she could survive the contretemps.

Gore, when asked where he stood on the clemency offer, told reporters he was waiting for the "analysis." Later, in a less-than-glowing-endorsement, he said he would not "second guess" the president.

Bush too has disappointed some Hispanic activists with his refusal to attend several major conventions this summer. Hispanic Democrats also charge that Bush--and his Republican Party--have been hostile to the concerns of the working poor, many of them Hispanic.

At the Gore rally, California Lt. Gov. Cruz Bustamante, criticized Bush for his opposition to gun control, the high number of Hispanic children in Texas without health insurance and low graduation rates among Texas Latinos. Referring to a popular salsa song, he said: "If anybody thinks that George W. Bush is good for Latinos, they are living 'La Vida Loca' [The Crazy Life]."

Gore, who received a rousing welcome, bragged to the audience that his first grandchild was born on July 4. "My next one I hope will be born on Cinco de Mayo."

CAPTION: First lady Hillary Rodham Clinton holds camera at arm's length to get picture of her and admirer at Congressional Hispanic Caucus dinner.