Washington — Heartened by what many economists see as the end of the recession, the Reagan administration is looking for signs that it has reached its own political nadir and is ready to rebound.
A turnaround in spirits at the White House seems to have occurred already. President Reagan during the weekend openly praised the virtues of ''Reaganomics'' - a term previously used mostly in a negative sense by his critics.
But whatever the economic news, much of the political evidence still seems to be running against the President.
A trial state-by-state electoral race between Reagan and Democrats Walter Mondale and Sen. John Glenn of Ohio, compiled by Republican professionals, shows Mr. Reagan lagging even more sharply than in similar matchups late last year. The latest GOP analysis shows Mr. Mondale leading Reagan 245 electoral votes to 145, with 148 in doubt. Senator Glenn would defeat Reagan 203 electoral votes to 151, with 184 in doubt.
With 270 electoral votes needed to elect a President, the GOP analysis shows Reagan as vulnerable to the Democrats as Jimmy Carter was to Reagan in the summer of 1980. Enough time remains to reverse these results, Republican strategists claim. An economic recovery is counted on to help.
''Assuming a recovery, and assuming Reagan runs, the presidential race for Republicans is close at worst,'' says one GOP professional.
But other evidence also points to heavy uphill slogging for Reagan. His standing in public opinion polls has continued its 1982 pattern, eroding steadily by a point or two a month. In mid-January Reagan's job approval rating fell below 40 percent for the first time, according to a Gallup poll.
More significant, the public has been abandoning key Reagan priorities, particularly defense spending. Public worries about nuclear war have shown a dramatic rise, making Reagan's negotiations with the Soviets more crucial to him politically.
The deficit problem - with Washington economists warning of $190 billion deficits and more in the fiscal years ahead - apparently has not yet crystallized in the public's thinking. But Democrats contend that deficits and unemployment will be the two big issues of the 1984 election.
''We've had a year of declining interest rates and inflation,'' says one Democratic strategist. ''The deficit is just starting to dawn on people - the size and scope of it. It's hard to believe the American people - whether Wall street or Main Street - are going to tolerate $200 billion deficits.''
''The deficit problem was there in Carter's last year,'' the Democrat concedes, ''but it was not recognized. The tinder was dry, as they say. Reagan's defense buildup, tax cuts, recession were the spark.''
For the public, deficits are likely to serve as a reminder that the Republicans haven't found it much easier to solve the nation's basic economic troubles than did the Democrats.
The public all along has been ambivalent about Reagan's attempt to cut government spending. Asked generally whether government was ''too big,'' they have agreed. Asked about specific spending programs, they have opposed cutbacks. Even the deficit issue is not likely to alter their view.
''I think people are going to decry the deficit and decry the cuts in social programs,'' says Burns Roper, president of the Roper Organization.
Reagan is already losing support for his defense buildup.
''He's not going to get away with $8 billion in defense cuts,'' says Mr. Roper of Reagan's proposed trim in defense outlays for fiscal 1984. Many Republicans on Capitol Hill want cuts of $15 billion or more.
''People now say we're spending too much on defense,'' Roper says. ''There's been a dramatic turnaround the past two years. In December 1980, 56 percent of the public said we were spending too little on defense. Now only 19 percent say that.''
Despite Washington's preoccupation with deficits, the public still thinks government isn't spending enough on jobless benefits, big-city problems, the environment, public transportation, energy, education, drugs, health, and crime. Only in defense, welfare, space, and foreign aid does the public think government is spending too much, according to Roper and other surveys.
''There's a conflict within the individual,'' Roper notes about American attitudes toward spending. Reagan's rule has not resolved that conflict.
The President does not appear to be making much headway in his attempt to fend off protectionist sentiment. By almost 4 to 1, the public would favor restrictions on foreign imports even if this resulted in higher prices.
On the trade-off between deficits and taxes, the public would rather risk higher deficits to keep taxes at current levels. But 52 percent of the public would cancel next July's scheduled 10 percent tax cut to help balance the budget , a Roper survey shows.
As a backdrop to current arms talks, the prospect of nuclear war has been rising as a concern among Americans - from 55 percent who saw it as a major imminent problem in December 1978, to 65 percent in December 1980, and 71 percent in 1983.
In the Republicans' current electoral vote outlook, Reagan leads Mondale and Glenn in the West, 43 to 11, with California's 47 electoral votes in doubt. Reagan also leads in the South and border states, 64 to 55, with 45 electoral votes in doubt.
But in the Northeast, Mondale leads Reagan 78 to 14, with 24 votes in doubt. Glenn also leads in the Northeast 42 to 14, but with several big states like New York and New Jersey in doubt. And in the Midwest, Mondale leads 81 to 24, with 32 votes in doubt, and Glenn leads Reagan 75 to 30.