If you’re old enough to remember the tumultuous protests of the Vietnam War era, you probably remember the ideological combat waged on car bumpers.

People who supported the war slapped “America: Love It or Leave It” bumper stickers on their cars. To which those who opposed the war responded, “America: Change It or Lose It.”

“Patriotism” means many things to many people. But one thing should be obvious to anyone lucky enough to be a citizen of this country: No political party has a lock on it.

For Republicans, that should have become uncomfortably clear during the Democratic National Convention, when the party of traditionally unherdable cats became a flag-waving, “Born in the U.S.A.”- singing single-celled organism.

“For everyone here and everyone watching, I want you to proudly claim your patriotism,” said Michigan Rep. Elissa Slotkin, a former CIA officer who served in Iraq. “You are here because you love your country. Do not give an inch to pretenders who wrap themselves in the flag but spit in the face of freedoms it represents.”

The Democrats’ full-throated embrace of patriotism discombobulated Republicans, who have always tried to claim the flag and freedom as their own.

“These American flags are sort of startling to me,” said CNN political analyst Scott Jennings, a longtime advisor to Senate Minority Leader Mitch McConnell who rarely misses a chance to insult Democrats. “Normally you guys are burning these things, but tonight, you’re waving them.”

The Wall Street Journal’s Peggy Noonan was also annoyed by what went down at the DNC. “They stole traditional Republican themes (faith, patriotism) and claimed them as their own,” she wrote.

Republicans have abandoned the values they traditionally embraced. In the past, you could define the GOP by its commitment to a strong national defense, free-market capitalism, lower taxes and limited government.

Now it is the party of Trump. That necessarily means Republicans have no consistent ideology.

For instance, Trump crowed about appointing three of the ultraconservative Supreme Court justices who overturned Roe vs. Wade and, as a candidate in 2016 and during his presidency, vowed that he would sign a national abortion ban. But now that he understands that stripping women of a fundamental right hurts him and other Republican candidates politically – and will continue to hurt them – he has backtracked.

He has trashed immigrants seeking better lives in the U.S. and fomented paranoia about those coming across the southern border. But when a bipartisan immigration enforcement bill was finally hammered out last year, he demanded that Republicans withhold their support. Why? So he could continue hammering Democrats over immigration.

Loving your country means being able to grapple honestly with its history and hold contradictory views of it in your head: America is a country founded on freedom, and America is a country founded on slavery. The flag is a beloved symbol of America, and Americans have a constitutional right to burn it if they choose.

That is what the Supreme Court ruled in 1989. And even the cranky conservative Justice Antonin Scalia agreed. “If it were up to me, I would put in jail every sandal-wearing, scruffy-bearded weirdo who burns the American flag,” Scalia said. “But I am not king.”

Last week, the man who would like to be king wrongly implied that Democrats burned flags during their convention.

“They’re burning American flags all over the place, and the fake news doesn’t want to show it,” Trump said. (There was one widely reported instance of pro-Palestinian protesters outside the convention burning American and Israeli flags.) Anyone who burns a flag should spend a year in jail, he said.

“They say, ‘Sir, that’s not constitutional,’ ” he said. “We’ll make it constitutional.”

In the aftermath of the 9/11 attacks, patriotic fervor surged in every corner of America. Flag sales skyrocketed. In the months after the attacks, it was not unusual to see American flags flying everywhere. Even in liberal bastions, Americans who had eschewed the flag suddenly waved it. Left-wing baby boomers who came of age during Vietnam and the civil rights era, who were rightfully skeptical of performative patriotism, embraced the flag as never before.

It was a rare moment of national unity. Before long, however, President George W. Bush’s misbegotten war in Iraq shattered the sense of oneness.

During President Obama’s first White House run, he decided to stop wearing a flag pin on his lapel as a gentle protest against the Iraq invasion. Republicans, already bent on “othering” him, were apoplectic.

“My attitude is that I’m less concerned about what you’re wearing on your lapel than what’s in your heart,” Obama said at the time. “You show your patriotism by being true to our values and ideals.”

It was true then. It is true today.