Remember the federal budget deficit?

Do you also remember how Republicans used to rail against it and how Democrats used to ignore it? Republicans said the deficit would keep growing and would bankrupt the nation. Democrats insisted that the government needed to “invest” public money on public projects.

Flash back to the 1980 presidential campaign.

• GOP nominee Ronald Reagan’s campaign ran TV ads that parodied House Speaker Tip O’Neill and the Democrats in Congress as wasteful spenders. President Carter oversaw a deficit that “ballooned” to about $40 billion.

Reagan won the election in a landslide.

What happened then? President Reagan fought for tax cuts and exploded defense spending. The result: the federal deficit effectively tripled.

Let’s move ahead to the 1992 election.

• Democratic nominee Bill Clinton ran against President George H.W. Bush, proclaiming “It’s the economy, stupid.” The nation was struggling through a recession. Clinton won the election. Then the Republicans took control of Congress after the 1994 mid-term election.

What happened after that? The Democratic president, working with the Republican-led Congress, balanced the budget. Clinton left the White House in 2001 and the budget was running a hefty surplus.

• Republican George W. Bush was elected in 2000. Then came the 9/11 terrorist attacks. President Bush pushed through more tax cuts, but then took the nation to war against terror groups overseas. The result of that effort? The deficit returned and exceeded $1 trillion annually.

But the argument evolved into something else. It didn’t matter that the deficit was exploding, the president and his allies contended, because it constituted a minuscule portion of the Gross Domestic Product. Didn’t the vice president at the time say, “Deficits don’t matter”?

Well, I guess they did.

• OK, now we come to the 2008 election. The economy has tanked. Financial institutions are going under. The housing market has crashed. So has the auto industry. The deficit was exploding.

Democrat Barack Obama won the election. He got Congress to kick in billions of dollars to jump-start the economy and bail out some of the leading industries.

What happened then? The economy began to recover. The jobless rate, which zoomed to 10 percent, began inching its way back down. Today it stands at 5.1 percent.

Oh, the deficit? It’s been cut by two-thirds.

It’s still too great. It’s a long way from the surplus delivered by President Clinton and his friends in the GOP-controlled Congress.

However, the traditional argument delivered by Republicans that deficits are bad and that Democrats are to blame for spending us into oblivion no longer is relevant.

Just think: The presidential campaign that’s unfolding before us has been called one that defies all conventional wisdom.

I believe the history of the federal budget deficit suggests conventional wisdom got tossed aside long ago.