A Democratic ''sell-out'' on the controversial Simpson-Mazzoli immigration bill could deflate Hispanic community enthusiasm for the Democratic ticket this election season, say Hispanic delegates at the convention here.
The party's 290-member Hispanic delegation has been divided most of the week over how - or if - it should press the issue here at the convention. It's an internal battle that has pitted this minority's shining lights, like San Antonio Mayor Henry Cisneros, against rank-and-file ''progressives.''
Although a majority of House Democrats voted against the bill last month, enough voted with the Republicans to pass it, 216 to 211. A conference committee later this summer will try to resolve differences between that measure and one passed by the Republican-controlled Senate last year.
Many Hispanics here want to see party leaders use their muscle to get Democratic legislators to vote against the bill. So far, they say, not enough pressure has been brought to bear by leaders like Walter Mondale, whose labor backers initially supported the bill before turning against it.
The immigration bill is objectionable to many Hispanics chiefly because of two provisions, one requiring an identity card and the other providing for sanctions against employers those who hire illegal aliens. These provisions, Hispanics suggest, invite discrimination against brown-skinned people.
''If Mondale is the nominee and Simpson-Mazzoli is passed, then I think it will have a substantial effect on the (Hispanic) vote. . . . It'll be difficult to mobilize the vote,'' says Colorado State Rep. Philip Hernandez, a Hart delegate. ''It's going to be very hard to go back and say to our people, 'Vote for the Democrats who gave you Simpson-Mazzoli.' And the Hispanic vote is very important in the West, Southwest, and the South.''
Discontented Hispanic delegates say the platform plank on immigration is too vague in its reference to supporting policies of ''humane treatment'' for all people - that it should specifically say the party does not support Simpson Mazzoli.
Though all Hispanics here oppose the bill, the debate this week centered on an attempt by League of United Latin American Citizens (LULAC) president Mario Obledo to get Hispanics to abstain on the first presidential ballot. At this writing, it was not certain whether any would do so.
Leaders such as Mayor Cisneros, New Mexico Gov. Toney Anaya, and US Rep. Edward R. Roybal of California urged Hispanic delegates not to take up the issue at the convention.
''This has to be resolved in Congress by turning votes around,'' argued Mr. Cisneros. He pointed out that Walter Mondale has already said he is against Simpson-Mazzoli and that a convention gesture would only help Ronald Reagan by showing disunity among Democrats.
Denver Mayor Federico Pena, a Hart delegate, was the only Hispanic elected official to support abstention. Some delegates suggested that the abstention issue was drummed up by the many Hispanic Hart supporters as a way to benefit their candidate as much as to emphasize discontent with the immigration bill.
Frank Contrera, a Mondale delegate who is a state education official from San Marcos, Texas, said the immigration bill controversy will not turn Hispanics away from the party, or even from the leaders who are urging a moderate stand.
''The fact that Democrats are voting in favor of this legsilation should give us incentive to go back and campaign'' harder for the Democratic ticket, he says.
The common denominator among all factions of the Democratic Party is the desire to unseat President Reagan, suggests Maria Berriozabal, a San Antonio City Council member and Mondale delegate. Against this backdrop, she argues, Hispanics will support the Democratic ticket no matter what the outcome of Simpson-Mazzoli.
Some contrast the ''old guard'' and ''new guard'' of Hispanic leaders and suggest that the old guard remains oriented to the party establishment. But Ms. Berriozabal counters that she and Cisneros are at a ''grass-roots level'' that could hardly be considered ''upper establishment.''
Anita Del Rio, national vice-president of LULAC and a delegate here, says she supports any strong statement Hispanics want to make on the Simpson-Mazzoli bill. But she defends the moderate stance of leaders like Cisneros who have been successful in their own way at becoming strong within the Democratic hierarchy. (Cisneros was interviewed as a potential Mondale running mate.)
Though there is disagreement on political style among the Hispanic delegates here, Ms. Del Rio says that there is a strong agreement that Simpson-Mazzoli must be defeated.
Despite the turmoil within the Hispanic caucus, she insists, a clear message is being sent to the party's nominee: ''After we leave the convention floor, whoever the candidate is will sense that Simpson-Mazzoli is a time bomb that could explode'' if not handled correctly.