BOGOTA, COLOMBIA, JUNE 1 -- A surprisingly strong showing in last Sunday's presidential elections has put a former guerrilla commander, Antonio Navarro Wolf, in the center of the sharpest realignment in Colombian politics this century.

The 41-year-old engineer, who finished third in Sunday's voting with 13 percent, ahead of the traditionally strong Social Conservatives, was an architect of the peace plan between the M-19 guerrillas and the government that was implemented in March.

In 1985, as a member of the M-19 high command, he lost a leg in a grenade attack that also resulted in a permanent speech impediment. He is thin, scholarly and professorial, not usually winning qualities in a Latin American politician.

The Liberal Party and the Social Conservative Party have dominated Colombian politics for decades, and other parties have been unable to break into the system.

But with the Social Conservatives, the second-largest party, badly split and many voters abstaining from this election, the M-19 appears to have capitalized on the country's hunger for change, political analysts said.

President-elect Cesar Gaviria of the ruling Liberal Party received only 48 percent of the vote in elections with the lowest voter turnout -- 46 percent -- in recent history, forcing him to look to other political forces to consolidate his government. His advisers say he will offer a high-visibility post to the M-19.

Navarro says his party will play a major role in an assembly being convoked to rewrite the constitution, which he sees as a chance to bring other armed groups into the system. The M-19 is to be given a significant bloc of seats. Exactly how the assembly will function has not been decided.

The M-19 is the only one of Colombia's four guerrilla groups to lay down its arms and enter the political system, and its success has been stunning in a country where the left had never won more than 4.5 percent of the vote and where about 1,100 leftist politicians have been killed since 1985.

In addition to running third nationally, the M-19 won the only four provincial capitals in which Gaviria trailed, including Barranquilla, the nation's fourth-largest city.

"We are the political phenomenon of the 1990s," Navarro said. "We are growing rapidly, and we aspire to be the majority party by the year 2000."

The M-19's initial presidential candidate and commander-in-chief, Carlos Pizarro, was assassinated on April 26 aboard a commercial airliner, but the group decided to stay in the elections with Navarro as its candidate.

The M-19's willingness to stay in the system despite Pizarro's assassination won high praise from President Virgilio Barco.

"I want to underscore the M-19's courage and commitment to peace," Barco said in a televised speech. "I want to thank candidate Antonio Navarro and his followers for the vote for peace and democracy they offered today."

Navarro is getting almost as much attention in the local press as Gaviria. He turns down few interview requests because, unable to travel for reasons of personal security and with little money to get his message out, he must take advantage of news coverage. He receives interviewers in an office with bulletproof windows, guarded by dozens of guards, a mix of M-19 friends and state security forces.

Navarro said his party would demand the governorships of the fourprovinces where he won elections. Governors are appointed by the central government, not elected. Those close to Gaviria said it is not likely the M-19 would be put in charge of the economically and politically crucial Atlantic coast region, where it won in Barranqilla. However, most major cities, whose new mayors took office today, gave the M-19 important administrative posts.

The success of the M-19 is paying dividends for the country, which has a long history of guerrilla uprisings. The Marxist Popular Liberation Army has begun negotiations with the government and halted offensive activities. The largest and oldest rebel group, the Revolutionary Armed Forces of Colombia, has expressed interest in talks, but they have not begun. Only the hard-line National Liberation Army has vowed to carry on the armed struggle.

Navarro said he would seek alliances with "progressive forces," and has led the movement away from orthodox Marxism.