Last night at the Hilton International Ballroom, the Congressional Hispanic Caucus showed it has emerged as a political force. At the dais sat the powers behind the caucus, the eight congressmen who espoused the theme of their fifth annual symposium, "Su voto es su voz" (your vote is your voice).

In the audience sat evidence of their recognition: Democratic National Chairman Charles T. Manatt, Joan Mondale, wife of former vice president Walter Mondale, a host of congressmen and more than 1,000 supporters of the U.S. Hispanic community.

The rhetoric was lyrical and forceful, reminiscent of civil rights champion Martin Luther King Jr.

"We have to stand up to J. Peter Grace and Clare Boothe Luce, who have no business representing the federal government let alone the White House," instructed caucus chairman Rep. Robert Garcia (D-N.Y.), referring to two Reagan administration personnel whose comments about welfare had deeply offended members of the Hispanic community. "We are a solid and productive community and have nothing to be ashamed of."

The caucus, which is fairly young, was strong enough to gain an audience with President Reagan on Wednesday. In that meeting, as in the president's speech the same day before the National Black Republican Council, Reagan and Vice President Bush sought to establish their record as an administration very much concerned with minority issues. But the result was mixed feelings on the part of the caucus.

Ray J. Garcia, co-chairman of the National Hispanic Council for High Technology Careers, said his meeting with the president and vice president left him unconvinced, "but," he noted, "Mr. Reagan is a warm and persuasive speaker."

"He even mentioned 'Mi casa es su casa,' " said Garcia's wife Gloria, mentioning the president's reference to his meeting with Mexican president Jose Lopez Portillo earlier this year.

"Baloney!" said Garcia, emphasizing his distrust of the president's speech. "The Reagan administration has not at all served the Hispanics from day one."

At dinner, though all were anxious to get on the dance floor, the audience sat patiently through a lengthy televised program that included speeches from actor Jose Ferrer, the eight caucus members and a special presentation to Vera Clemente, the widow of Puerto Rican baseball star Roberto Clemente.

Rep. E. (Kika) de la Garza (D-Tex.) reminded the group of the distance they had covered in the years since his childhood, when his neighborhood was known as "el barrio de la escuela catolica" (the neighborhood with the Catholic school).

"By the grace of God," said caucus member de la Garza, echoing once again the symposium's theme, "by the Democratic party and by 'el barrio de la escuela catolica,' su voto es su voz."