Democrat ticket united - except on some issues. DUKAKIS VS. BENTSEN

Contra aid could become a red-faced issue for the new Democratic presidential ticket within the next few days. Key Senate Democrats, responding to grim news out of Managua, are hammering out a compromise package of military aid for the contra rebels who have fought Nicaragua's Marxist government.

A Senate showdown on the issue could find Michael Dukakis on the other side of an emotional issue from his own vice-presidential nominee, Lloyd Bentsen.

Governor Dukakis, an unyielding opponent of military aid to the contras, has called such assistance ``illegal and immoral.''

Senator Bentsen, who has championed contra aid for years, says it is the only way to prod Nicaragua toward democracy.

The new pressure for Washington to supply aid to the ``freedom fighters'' has come directly from Nicaragua. In recent weeks, the government has cracked down on the news media, labor unions, the Roman Catholic Church, private businesses, and other longtime critics.

``This government is not going to be hounded out of office,'' declares Alejandro Bendana, secretary general of Nicaragua's Foreign Ministry.

But the crackdown on pro-democratic forces has prompted a move by some Senate Democrats to release $18 million in frozen military aid for the contras, unless the Nicaraguan government reverses course.

Among those working for a compromise on military aid are said to be Senate majority leader Robert Byrd of West Virginia and Sen. David Boren, chairman of the Senate Intelligence Committee.

Senator Boren is a personal friend of Bentsen, but he denies reports that he is acting as a Bentsen surrogate on the contra aid package.

Politically, the Senate vote could carry high embarrassment for the Democratic ticket, especially if Bentsen casts his ballot in favor of military aid.

Republicans are hoping to exploit the differences - challenging voters with the question: ``If you vote for the Democratic ticket, what policies are you really voting for?''

There are a number of sensitive issues where Mr. Dukakis and his running mate have sharply different views, including the B-1 bomber, the MX missile, the Midgetman missile, gun control, arms sales in the Middle East, school prayer, the death penalty, and abortion.

But none is more clear-cut than their views on contra aid, which has become a Democratic litmus test for presidential candidates. As one Democrat on Capitol Hill puts it:

``This isn't just any issue. This has become one of the most heated partisan issues of the decade. The Democrats have invested so much emotional commitment in their positions that it creates more tension than any other.''

There is no doubt where Dukakis stands. He once told the Monitor in an interview that support for the contras by President Reagan was ``the worst fiasco we've been involved in in my lifetime.''

At a speech in Chicago last year, Dukakis said: ``What we are doing in Central America today is a violation of US, as well as international, law.''

Another time, he said: ``We put ourselves above the law. We showed our neighbors a fist when they needed a helping hand.''

And again: ``We need leadership that will stop the shooting war against Nicaragua and start the war against poverty and injustice throughout Latin America.''

Bentsen clearly disagrees with Dukakis's renunciation of force. As recently as Feb. 4, he voted for President Reagan's $35.25 million request for continued aid to the contras. He backed a $100 million aid package ($70 million military) in 1986.

In a speech in the Senate, Bentsen explained his votes: ``I ... support continued aid to the contras, including military aid, because I believe that the military pressure of the contras is the only reason we have seen any movement at all toward democratization in Nicaragua. ... I am convinced that the continuation of this pressure is the only guarantee we have that the gains made thus far in Nicaragua will not be temporary ones, to be thrown out by the Sandinistas once the contras have been abandoned.''

There are a number of other issues where the men disagree:

The MX missile. Dukakis charges that the missile will not add to American security and ridicules a plan to base them on rail cars. Bentsen says of the MX: The US cannot ``afford to write off one leg of our strategic triad - particularly not at a time when the Soviet Union is moving inexorably ahead with its military buildup.''

Midgetman missile. Dukakis calls it ``not essential to maintaining an effective deterrent.'' Bentsen supports it.

Support for UNITA. Dukakis calls assistance to the UNITA rebels fighting a leftist regime in Angola ``absolutely bizarre. We've got a situation where we're supporting this group, whose principal patron is South Africa, which attacks American oil companies that are defended by the Cuban army.'' Bentsen favors aid to UNITA.

School prayer. Dukakis opposes prayer in public schools. Bentsen favors a constitutional amendment to ``clarify the right of our children to pray in school.''

Abortion. Dukakis supports federal funding of abortion. Bentsen opposes federal funding except in special cases, such as rape, incest, and danger to the life of the mother.

Death penalty. Dukakis opposes it. Bentsen says it ``should be used only in the most extreme cases.''