Memo to Democrats on the Good Friday report that the U.S. economy added 162,000 jobs in March: True, any increase is obviously better than a poke in the eye with a sharp stick — but keep the champagne on ice, and put away the decorations. Any time for celebration is still a long way off.

Mark Shields

Mark Shields

Don’t just take my word for it. Consider this. In the past 98 years, only two Democratic presidential nominees have defeated elected Republican presidents. Unfortunately, nobody from Franklin D. Roosevelt’s winning 1932 campaign is available for interviews.

But two of the leaders of Bill Clinton’s winning 1992 campaign, strategist James Carville and pollster Stan Greenberg — who were guests last week at a Washington breakfast hosted by the Christian Science Monitor — had some blunt advice for nervous Democrats facing voters in 2010.

Evoking the earthy analysis of Rep. Barney Frank, D-Mass., that it will be difficult for Democrats to run on the campaign slogan, “Things would have sucked worse without me,” Carville reminded his friends in the Obama White House that “the hardest thing to do in all of political communications is: How do you deal with a bad but somewhat improving economy?”

Carville knows this from happy, personal experience in 1992, when Clinton was challenging incumbent President George H.W. Bush on the issue of the nation’s supine economy. The U.S. unemployment rate was falling from 7.8 percent in June to 7.3 percent in October. But news of those improving numbers could not prevent Bush’s share of the national vote from falling a precipitous 15 percent, from a winning 53 percent in 1988 to a losing 38 percent in 1992. Perception is reality, and the perception persisted that the nation’s economy was bad.

Greenberg agreed: “White, blue-collar voters, particularly males, took a big hit in this (current) recession. As the elites try to make the case (during the 2010 campaign) that this is coming back and economic policies work, they’re going to get angrier and angrier.”

To reinforce his point, Greenberg recalled the negative reaction of a group of swing voters he was monitoring to President Barack Obama’s boast during the State of the Union speech that his administration had brought the U.S. economy “back from oblivion.”

Any politician, this year, who tells hurting voters they ought to be more optimistic because of reports of increased corporate profits or big hikes in the Dow Jones average will completely deserve the intense hostility he gets.

For Democrats, Greenberg added another sobering note involving three key Obama 2008 constituencies — unmarried women, Latino voters and young voters. For them, “the recession has gotten much worse, and they have gotten more pessimistic.”

To reach these understandably discouraged and dispirited voters, Carville revealed he had told White House operatives: “I wish you would be more about conveying there is a strategy … a plan that is in place.”

In my opinion, not Carville’s or Greenberg’s, Americans today can be compared to passengers on a subway train that has abruptly stopped between scheduled stops, plunging everyone into darkness. What people are most looking for is the reassuring, informed, authoritative voice who explains what went wrong, what is being done to correct it, what each of us can do to help and when we can realistically expect to return to normal conditions.

Democrats in 2010, like Republicans did in 1992, will learn again the wisdom of political journalist Jack Germond: “When the economy is bad, the party in power is blamed. When the economy is good, people look at other issues.”

Mark Shields is one of the most widely recognized political commentators in the United States. The former Washington Post editorial columnist appears regularly on CNN, on public television and on radio. Click here to contact him.