Washington — Jose Napoleon Duarte, having won over his fellow Salvadoreans in his bid for the presidency, now takes his campaign personally into the halls of the US Congress.
The Christian Democrat, due to arrive in the United States this weekend, already has a long history of dealing with American lawmakers, many of whom see him as the best hope for the future of Central America. He is expected to try to translate that goodwill into maximum US aid, with minimal strings attached.
Mr. Duarte is widely expected to be successful.
''He's a very impressive character,'' says Richard N. Howill, deputy assistant secretary of state for Inter-American Affairs. The fact that Duarte has fingers missing and bears the scars of torture and combat gives credence to his claim ''when he says, 'I've prepared my entire life for the role I'm about to assume,' '' the State Department official says.
Even one of the administration's chief critics on Central America policy, Rep. Clarence D. Long (D) of Maryland, credits Duarte with being a ''gutsy guy.'' The chairman of the subcommittee on foreign operations says, ''Anybody who is imprisoned and tortured and still comes back to run for office, you've got to give him a good deal of applause.''
Duarte, who was once elected to head his government and then imprisoned by the military, served as acting head of El Salvador from 1980 to '82. He has established strong ties with many on Capitol Hill. Educated in the US at the University of Notre Dame, he has visited Washington frequently, while lawmakers have routinely visited him during tours of Central America.
Rep. Jim Leach (R) of Iowa, a member of the House Foreign Affairs Committee, has commented that Duarte has met with Congress on ''more substantive issues'' than has President Reagan.
But the Salvadorean President-elect is not guaranteed an easy path through Congress. On the one side, he faces skepticism that he will be unable to halt the right wing's ''death squads.'' On the other, he faces his most outspoken opponent, Sen. Jesse Helms (R) of North Carolina.
Harking back to the earlier Duarte rule, Senator Helms has charged that Duarte ''systematically imposed socialist reforms'' that included the ''socialist land-reform scheme created by the US State Department.'' Moreover, he points out that Duarte nationalized banks and export businesses and that his 1980-82 government included officials ''who are recognized as militant communists.''
The North Carolinian has also challenged the legitimacy of the Salvadorean election by asserting that the United States aided the Duarte forces against Roberto d'Aubuisson, the right-wing candidate whom Helms favored.
So far, Helms has found few allies for his anti-Duarte views.
''I think that anyone elected president of that country you're going to have doubts about,'' says Robert J. Lagomarsino (R) of California, a member of the House subcommittee on Latin American affairs.
''We all are favorably impressed with him,'' says Rep. Henry J. Hyde, a fellow Republican on the subcommittee and an ardent anticommunist.
''Duarte has no association with the right-wing death squads, so he's very acceptable as the beneficiary of aid,'' the Illinois conservative says.
But Representative Hyde and others concede that they have no extensive knowledge of Duarte's background.
The new Salvadorean chief, despite his personal popularity in the US, carries some baggage from his past. ''It's fair to say he's farther left than any Christian Democrat that I've ever known,'' says the State Department's Mr. Howill, pointing to Duarte's moves toward nationalization and land reform. ''All of these things have been in the socialist party platforms.
''He is very much a reformer,'' adds Howill. He affirms the Reagan administration's support, while adding that Duarte has made ''rash moves'' in the past that alienated the business community and military.
''Is he a moderate?'' asks Howill. ''I'd say he's left of center, but not doctrinaire.'' Howill also says Duarte is ''very, very sincere in saying that he plans to get the death squads under control.''
Meanwhile, liberal critics worry less about nationalization and more about whether Duarte can end human-rights violations. ''He's going to have to do some real talking to woo me,'' says Representative Long, who has a long list of requirements, ranging from a restructured judiciary that will convict death-squad participants to providing for impartial foreign observers as watchdogs of the Salvadorean military.
Mr. Long also wants assurances that Duarte is ''genuinely interested'' in a negotiated settlement with the leftist guerrillas fighting the Salvadorean forces.
Meanwhile, Helms is equally adamant in opposing talks with the guerrillas.
During the election campaign, Duarte walked gingerly over the negotiation question. He called for dialogue with the opposing forces and for including them in elections, but not in his government.
Duarte will probably need to chart an equally cautious course when he meets with members of Congress next week. He is already virtually assured of some economic and military aid for his country. A good impression could mean even more.