A sense of hope, the feeling of a new era dawning, is what many Colombians say they remember from the days nearly four years ago when Belisario Betancur, a political maverick with a populist touch and reformer's message, took over as president.

He promised a different approach to Colombia's chronic political violence, based on dialogue instead of combat. He spoke of modernization and of opening the traditional clubhouse of Colombian politics to broader participation, having himself created a national movement to reach beyond his Conservative Party constituency in the campaign.

But in a nation long torn by strife and controlled by powerful established interests, such expectations of change were likely to be frustrated. Now, in the final months of the Betancur administration and in the heat of the campaign to replace him, Army and guerrilla forces are battling with renewed ferocity. A recent opinion poll reported by a local news magazine showed Colombians to be pessimistic again.

As usual, only half the eligible voters cast ballots in congressional elections March 9. Those who did generally voted for candidates from one of the two traditional parties that have dominated Colombian politics since the northern part of South America won independence from Spain in 1819.

While Betancur, 63, retains the affection of many Colombians, many have grown disillusioned with his government. He cannot run for reelection. In the congressional elections, the Liberal Party won 49 percent of the vote against 38 percent for Betancur's Conservatives.

A bid by a dissident Liberal Party figure, Luis Carlos Galan, to establish a third political force on a platform of renovation foundered. Galan's New Liberal Party drew only 7 percent of the vote, less than its 10 percent showing in 1982, prompting Galan to withdraw from the presidential campaign, which ends May 25.

The results of the March election seemed to negate the notion that Colombia had become less inclined to what is known here as electoral "clientism." Instead, the traditional bipartisan system was reaffirmed, and the kind of experimentation represented by Betancur appeared to have lost appeal.

Some commentators attributed this to the power of the old party machines. Others saw the vote as a reaction, at least in part, to several recent shocks, including the violent attempt last November by Movement-19 (M19) guerrillas to take over the Palace of Justice and the explosion the same month of Nevado del Ruiz volcano, which triggered a mud avalanche that buried the town of Armero.

"After the Palace of Justice, Armero, recent guerrilla massacres, all these things have created in people a certain fear of the unknown," said Enrique Santos Calderon, a columnist for the Bogota daily El Tiempo and member of the prominent family that owns the paper.

Betancur, reflecting last month on his period as president, appeared not to be very disappointed about the way things have turned out.

The peace process, he said in an interview, had passed "a point of no return," at least concerning the Revoluionary Armed Forces of Colombia, or FARC, the country's oldest and largest guerrilla group. Betancur took particular pride in having incorporated the Revolutionary Armed Forces into the democratic process. Its newly established political party, the Patriotic Union, won less than 2 percent of the recent vote but seven of 313 congressional seats.

Betancur cited a law providing for the election of mayors starting in 1988 -- they are now appointed -- and others passed last year governing the creation of political parties and expanding the right to official information as examples of how his administration has widened the tight circle of Colombian politics.

While some of the urban and agricultural changes he sent to Congress remain bottled up in committees, he said that during his term the illiteracy rate dropped from 20 percent to 8 percent. He also said the government was close to reaching its target of 400,000 new housing units.

Even some of Betancur's keenest critics conceded that this unusual politician had left a positive mark.

"He has brought the government closer to the people, removing some of the mystique that had surrounded it," said Alfonso Lopez Michelson, a Liberal leader and former president.

"A current of public sympathy is still with him," said Fernando Cepeda, a law professor and Liberal Party strategist. "Many say the problem has not been with Betancur but with the system, the political parties, the structure in Colombia. Betancur has managed to continue to look like a good and nice man."

In a move welcomed by the United States, Betancur has also cracked down on drug traffickers and granted more than a dozen U.S. extradition requests.

But measured against his own starting pledges, much of Betancur's program is unfinished. Three guerrilla groups -- M19, the Popular Liberation Army and Workers' Self-Defense -- that signed truces with the government are again at war.

"The fighting now is more visible than a few years ago," said Antonio Caballero, editor of Semana magazine. "It has come out of the jungles, into the cities of Bogota, Cali and Medellin."

Even the Revolutionary Armed Forces, despite a nationally televised ceremony last month in which its truce was extended indefinitely, continues to kidnap and extort in some regions.

Social legislation that the guerrillas had expected would follow the cease-fires has been stalled in Congress.

"Of critical importance is Betancur's relative political isolation," concluded an analysis published in January by Americas Watch. "The movement he created for his campaign virtually disappeared after he assumed office. Betancur lacked strong support within his own Conservative Party for his reforms, and the opposition Liberal Party controls about two-thirds of Congress. Moreover, Betancur attempted initially to rely on his personal prestige and popularity to pursue his agenda, circumventing the traditional political machinery.

"While blaming Congress for failing to move on various legislative proposals, Betancur's government has been unwilling or unable to proceed adroitly enough, within the given political rules of the game, to secure congressional support," said the report, echoing a view widely held among Colombians.

Fiscal constraints also hampered the implementation of some social measures. A precipitous drop in foreign exchange reserves in 1984 pushed Betancur to adopt an austerity program.

On the international front, Betancur had hoped to carry his banner of peaceful dialogue to Central America. He was a founding member in 1983 of the Contadora movement, which has grown to eight Latin American states advocating negotiations to settle Central American conflicts.

But this initiative, too, has run aground, due to stormy relations between the Sandinistas and the Reagan administration.

Some Colombian and U.S. analysts suspect that in Betancur's remaining months in office -- he steps down in August -- the Colombian leader may try to rush Nicaragua and other Central American states to sign a compromise document, so that he will have something concrete to show for his efforts.

The Liberal Party's presidential candidate, Virgilio Barco, 65, is widely favored to win the presidential election in May. A graduate of the Massachusetts Institute of Technology with an American wife and a long public service career, Barco is thought to be less likely to challenge U.S. policy in Central America.

Barco and the Conservative Party candidate, Alvaro Gomez, have said they would continue the peace process with Colombia's guerrillas, although Barco has also spoken vaguely of the need for "a firm hand" in dealing with the rebels.