POLITICS : Argentine Voters Cast Doubts on Top Parties’ Tango : Elections for an assembly show erosion for the Peronists and their main opponents. Analysts cite a deal on constitutional changes.

BUENOS AIRES —  In the relentless chess game of Argentine politics, the reigning grand master seems more vulnerable these days.

President Carlos Saul Menem dominated the board a few months ago, and his strategy for seeking a second term in office looked all but unassailable. Now, however, Menem’s quest is plagued by question marks.

Recent elections for a constituent assembly have shown that voters are restless and cannot be taken for granted, by Menem or anyone else.

The president’s Peronist party won 38% of the votes in the April 10 polling, down from 42% in elections for Congress last October. Former President Raul Alfonsin’s Radical Civic Union, the main opposition, fared even worse. The Radicals won 20% of the vote, compared to 30% in October’s congressional elections.

Analysts say the erosion of both parties’ polling power partly reflected weak public support for an agreement between Menem and Alfonsin on constitutional changes to be made by the new assembly. Alfonsin pledged his party’s support for removing a provision that bars presidents from seeking immediate reelection. The planned amendment would make Menem, 63, eligible to run for four more years after his current six-year term.

In return, Menem agreed to new checks and balances proposed by Alfonsin to limit presidential powers. He also accepted a provision that would require a presidential runoff election if the first round gives no candidate 45% of the vote, or 40% with a 10-point lead over the runner-up.

Some members of both Menem’s and Alfonsin’s parties have criticized the agreement, signed last November after secret negotiations. And some critics outside the parties, including author and political columnist Horacio Verbitsky, have cited unconfirmed reports that Radical leaders received millions of dollars from the Peronists as payment for the pact.

“There is no proof and probably never will be,” Verbitsky said in an interview. But he said the pact has the image of a shady deal among much of the public.

If the Peronists and Radicals stick to the pact, as expected, the constitutional amendments will be passed by the new assembly, which convenes May 25. The Peronists won 138 seats in the 305-seat assembly and the Radicals 75, enough for a combined majority.

But in next year’s elections, Menem is unlikely to have Radical support. And how strong other opposition groups may be by then is a question raised by the assembly elections.

The Big Front, a coalition of leftists and center-leftists, rose suddenly from insignificance to big-league status by winning 13% of the votes. The front is led by Congressman Carlos (Chacho) Alvarez, a renegade Peronist with presidential ambitions.

The right-wing Movement for National Dignity and Independence, or Modin, also made surprising gains in the April 10 vote, taking 9%.

If a constitutional amendment makes two rounds of presidential elections possible, voting in the first round could be split among parties looking for advantages in a small piece of the action, analysts say. And in the second round, they say, the support of emerging forces such as the Big Front and Modin could be open to negotiation.

That kind of scenario is a new element of insecurity for Menem in his quest for reelection. Another is increased public indignation over corruption scandals involving officials linked to Menem’s party.

Before the recent elections, several scandals made media headlines but somehow did not stick to the famous “Teflon” of Menem’s political image. But commentators say a major cause of Peronist losses in Buenos Aires on April 10 was a scandal involving one of the party’s assembly candidates.

Manuel Mora y Araujo, a prominent political pollster, said the election indicated that the corruption issue has become a problem for Menem.

Slip in Support

An agreement on constitutional changes may have weakened support for Argentine President Carlos Saul Menem and rival Raul Alfonsin. Menem’s Peronist party lost 4 percentage points, and Alfonsin’s Radical party slipped 10 percentage points.

April Elections For Constituent Assembly

Party Popular vote No. of seats Justicialist (Peronist) 38 138 Radical Civic Union 20 75 Big Front (leftist coalition) 13 32 Modin (right movement) 9 18 Others* 20 42

*includes null and blank votes

Sources: Ambito Financiero and Pagina 1/12 newspapers