Donald Trump is fabulously adept at taking credit for and exaggerating every bit of good news, especially good economic news. When the news is bad, he changes the subject. Trump is the master, but Republicans generally are skilled at fine-tailoring reality for their benefit.

Democrats are the opposite. They seem to assume that the public automatically sees the good things happening when they’re in charge. Like psychologically abused children, they internalize almost any criticism. That’s why rather than retell the story in the most flattering light, they dive into a defensive crouch. The inability to blast through the negative makes much of the public think them blameworthy.

We are now in the ninth year of a global economic expansion. For all but one year of it, Barack Obama was president. “Global” means that many countries are doing well. Some, meanwhile, are doing better than the United States. It’s not Trump’s economy.

The stock market has indeed posted lovely gains since Trump came into office. From his inauguration to Jan. 5, the day after the Dow Jones industrial average broke through 25,000, the market rose 26 percent. In the same period of Obama’s first term, however, the Dow gained 33 percent. (And Obama saw no need to trash the environment to make polluters richer.)

Did you hear Democrats loudly heralding Obama’s economic genius? Neither did I.

Since 1980, the biggest gain in the Dow during an eight-year presidency was 227 percent under Bill Clinton. The second-biggest was 149 percent under Obama. Coming in third was Ronald Reagan’s, at 135 percent. But to whom does American lore give the biggest plaudits for robust markets? Reagan.

Many factors other than the president influence the economy (and stock prices), but that’s not the point here. The point is that the flamboyant right-leaning media send out an 800-piece brass band every time a record is set or something goes well for two consecutive months when the president is a Republican.

You barely heard a peep from Obama when the Dow hit all-time highs during his presidency — and that happened 122 times. That may have reflected admirable modesty on Obama’s part, but as politics, it was close to malpractice.

After passage of the Affordable Care Act, Democrats running for re-election let right-wing attacks and misinformation about the program rule their campaigns. Rather than tout the achievement as the best new protection for Americans in decades — and make the headline the many millions who would enjoy health coverage for the first time — they vowed over and over again to “fix” the program, whose problems were minor. These nervous promises left the impression that the health care reforms were indeed seriously flawed.

Bill Clinton left the presidency with a budget surplus. The right keeps running the story that the only notable thing in Clinton’s eight years was his tryst with Monica Lewinsky.

Back then, people became so numbed by the Republicans’ incessant hammering — and refusal to address important issues — that they struck back in the subsequent midterm elections. Democrats gained five House seats, the second time since the Civil War that the president’s party added seats in a midterm.

Clinton left office with a higher approval rating than did Reagan. Yet the Democrat running to replace him, Vice President Al Gore, kept a distance between himself and Clinton during the campaign. Despite all the evidence that Clinton remained quite popular, Gore’s campaign chose to ingest the right’s propaganda that most Americans disliked him.

Gore lost the Electoral College by a handful of ballots in Florida. Trump wouldn’t have hesitated to make use of a superb salesman like Bill Clinton.

Democrats need band class.

Froma Harrop is a syndicated columnist. Follow her on Twitter @FromaHarrop. She can be reached by email at: fharrop@gmail.com.

Froma Harrop