Washington — Hispanics, these days, are faring poorly in the traditional American game of interest-group politics. Sure, Ronald Reagan had Hispanic leaders over for lunch last week. And both parties are scrambling to register Hispanic voters, and produce Spanish-language commercials.
But the nation's fastest-growing ethnic minority cannot get the support of either party on the issue it holds most dear: immigration reform. In general, ethnic group spokesmen say, they feel their political courtship is all flash and no substance.
''I think sometimes (politicians) take our community somewhat for granted,'' complained Raul Yzaguirre, head of the National Council of La Raza, at the end of last week's National Hispanic Leadership Conference. ''We demand first-class attention. Sometimes even our friends forget that.''
Hispanics are relative rookies in the political big leagues of the United States. Until the turn of this decade, they were virtually ignored by the national parties.
But their fast-growing political muscle can no longer be overlooked. The Hispanic population of the US increased 61 percent during the 1970s, to 14.6 million.
And most of those Hispanics are clustered in nine electorally important states. In Texas, for example, there are 1.4 million Hispanic voters. (Ronald Reagan in 1980 won Texas by 630,000 votes.)
''We're a swing vote. There are a lot of states where we make a difference,'' Mr. Yzaguirre said last week.
There is one problem with this picture, though -- Hispanics tend to stay away from the polls in large numbers. Their voter participation rate is much lower than that of either blacks or whites. Voter registration, Hispanic leaders say, is thus their priority. ''That's where we're going to derive our power,'' says Gloria Rodriguez, D.C. director of the National Puerto Rican Forum.
Three large Hispanic voter-registration projects have divided up the US and are busy signing up recruits. Leaders claim they will reach a goal of 1 million new registrations by November, bringing the pool of US Hispanic voters to 4.5 million.
Both parties are trying hard to win these voters' hearts. Traditionally, Hispanic groups (except Cubans) overwhelmingly vote Democratic. But Mr. Reagan won some 30 percent of the minority's vote in 1980, and the Republicans this year have again come courting Hispanics.
The Republican National Committee has three staff members who specialize in Spanish language radio ads, for instance, and ''Viva '84,'' a campaign to raise and spend $1 million on ''Hispanic outreach.''
Tirso del Junco, chairman of the Republican National Assembly, predicts Reagan will win ''better than 35 percent'' of Hispanic votes in '84. ''Basically , Hispanics are conservative,'' he says.
A Democratic Party spokeswoman retorts that her party has ''Hispanic Force ' 84,'' a voter-registration program. Hispanics really ''have no place to go but the Democrats,'' she says, considering how Reagan's policies have affected the underprivileged.
But the attention has not turned Hispanic leaders' heads. They feel much of the political courting is superficial, and that their substantive concerns are being ignored.
''The best example of this is the immigration bill,'' says Richard Fajardo, a staff lawyer for the Mexican - American Legal Defense and Educational Fund.
Mr. Fajardo is referring to is the Simpson-Mazzoli bill, a sweeping reform of immigration policy that the House is scheduled soon to debate. Hispanic groups strongly oppose it. They say a provision that calls for punishment of those who hire illegal aliens would result in discrimination against all who look Hispanic.
House Speaker Thomas P. O'Neill Jr., at Hispanics' insistence, had blocked the bill. But last fall he reversed his stand, and placed it on the House agenda. All indications from the White House are that the President, if sent the bill, would sign it. (Passage, however, is far from certain.)
''All too often, neither party focuses on the concerns of Hispanic Americans, '' sighs Joseph Trevino, legislation director at the League of United Latin American Citizens.
Under administrations of both persuasions, for instance, the Equal Employment Opportunity Commission has paid little attention to Hispanics, Mr. Trevino says. A recent government study found that the EEOC did, indeed, overlook cases based on ''national origin,'' instead of color.
Even the Supreme Court is now adding to Hispanic frustration with Washington. Two weeks ago, justices upheld the right of the Immigration and Naturalization Service to conduct sweeping searches of factories, seeking illegal aliens.