Washington — Despite the unfolding Iran-contra saga, President Reagan's popularity with American voters has been steadily moving upward since last winter's lows. The President, asserting Tuesday that ``all that lame-duck talk is for the birds,'' has nudged his public approval rating up to 54 percent in the latest surveys by Richard Wirthlin, the White House pollster. At one time it was only 40 percent.
Dr. Wirthlin's figures are confirmed by other recent polls, including one by Gallup. Wirthlin told a group of reporters at breakfast yesterday that he stands by his prediction that Reagan's ratings will move over 60 percent by year's end - unless the Iran-contra hearings in Congress produce a bombshell.
The President's main areas of strength are among young men (69 percent approve of the job he is doing), white-collar workers (62 percent approve), Roman Catholics (60 percent), and voters in the West (59 percent). As a group, women (46 percent) remain among the most skeptical.
Reagan appears to be gaining even though two-thirds of Americans feel the President is failing to tell the whole truth about the Iran-contra affair.
The White House, hoping to take the offensive after months of political stagnation, had Reagan back on the road yesterday in New Britain, Conn., to plump for his ``economic bill of rights.''
The bill includes the proposed balanced budget amendment, the line-item veto, and other policies designed to show the President's concern over continuing budget deficits in Washington.
Taking the political offensive should help the President's standing, Wirthlin says, as should the coming battle over confirmation of Supreme Court nominee Robert H. Bork. Conservatives are expected to rally around the White House as the Bork battle heats up.
The President, reportedly too busy to watch opening-day testimony by Lt. Col. Oliver North, nevertheless is keeping a close eye on the polls. He has met three times with pollster Wirthlin since mid-June to review the figures.
While Reagan's standing has improved, Wirthlin admits there are still serious problems.
A solid majority (55 percent) of the public believes that Reagan has done a poor job of getting to the bottom of the Iran-contra affair. Two out of three voters say flatly that the President lied about what he knew of the scandal.
Wirthlin says the Reagan White House has been caught in a whirlpool of public disillusionment brought about by a series of events: Gary Hart's downfall, the Ivan Boesky affair on Wall Street, evangelist Jim Bakker's problems, the corruption of US Marine guards at the American Embassy in Moscow.
Even Reagan, the ``great communicator,'' has been unable to extricate himself from the public distrust that has grown from this milieu.
Yet Reagan remains strong despite his problems. Wirthlin notes that, though most Americans believe he is lying about Iran-contra, 65 percent call him an honest person. Even more - 76 percent in Wirthlin's newest poll - say they like Reagan personally.
White House strategists hope that Colonel North's testimony, to be followed next week by that of Vice-Adm. John M. Poindexter, the former national-security adviser and North's former boss, will bring down the curtain on the scandal, at least insofar as Reagan is concerned. Without a ``smoking gun,'' presidential aides hope the story will die within the next few weeks.