MEXICO CITY : Key State Elections

Candidates from the ruling Institutional Revolutionary Party face stiff challenges Sunday in two gubernatorial elections and the threat of violence if the vote is believed to be fraudulent.

In the central farming state of Michoacan, the official party’s candidate, Eduardo Villasenor, is running against the Democratic Revolutionary Party’s Cristobal Arias. An Arias victory is considered crucial to the future of the left-of-center opposition party and its populist leader, Michoacan native son Cuauhtemoc Cardenas.

And in the northern border state of Chihuahua, the conservative National Action Party’s candidate, Francisco Barrio, faces the ruling party’s Jesus Macias as he tries to reverse a 1986 loss in a gubernatorial election he says was stolen by the government. That earlier loss prompted anti-government street demonstrations and a takeover of international bridges.