MEXICO CITY – The virtual tie between Mexico’s top presidential candidates in Sunday’s election is one of the worst possible scenarios for this country. It creates new political tensions and the prospect that whoever wins will be politically weak, with no working majority in Congress.

While President Vicente Fox won the 2000 election with 42 percent of the votes, the new president – whether pro-business government candidate Felipe Calderon or left-of-center former Mexico City Mayor Andres Manuel Lopez Obrador – will win with only 36 percent of the votes, according to most exit polls.

This is a bad omen. If Fox led a minority government that could not pass any major law through Congress, and was thus seen as a somewhat ineffective leader, whoever takes his place will have an even bigger challenge to pass laws and move the country forward.

Much of the problem stems from the fact that Mexico has a three-party system, in which the two opposition parties systematically block all initiatives coming from the government party. Most exit polls indicate that the next Congress will be almost evenly divided in three political blocs.

The exit-poll results also show that Mexico did not vote massively for either continuity or change. In a sense, it was a middle-of-the-road vote, in which more than a third of the people voted for the pro-free-market continuity offered by Calderon, more than a third for a reversion to the nationalist welfare state offered by Lopez Obrador, and a smaller number for a combination of both, offered by the once ruling Institutional Revolutionary Party (PRI).

If Calderon were declared the winner, it would suggest that many Mexicans feared the possibility of a radical change. Calderon’s campaign tried to paint his main rival, Lopez Obrador, as a radical leftist who would follow in the steps of Venezuelan President Hugo Chavez.

In a country that depends on the United States for nearly 90 percent of its exports, about 80 percent of its tourists and virtually all of its $20 billion in foreign remittances, there are always fears that a worsening of ties with Washington could hurt everybody’s pockets.

If Lopez Obrador were declared the winner, it would suggest that many Mexicans feel that the half-hearted free-market reforms of the past two decades have not done enough to reduce poverty.