MEXICO CITY : Strong PRI Showing?

In a midterm test of the ruling party’s popularity, Mexican voters will go to the polls Sunday to elect six governors, a federal chamber of deputies and half the members of the senate.

The official Institutional Revolutionary Party faces strong challenges from opposition candidates in governors’ races in the states of Guanajuato and San Luis Potosi. But the PRI, as the ruling party is called, is expected to do much better in this vote than it did in the 1988 elections, when opposition candidates won nearly half the congress and swept Mexico City.

The vote also is a test of new electoral laws passed last year and of the government’s ability to convince the public that it has conducted a free and fair election.