People change their opinions. As my husband says, “I always reserve the right to get smarter,” paraphrasing Konrad Adenauer, the former chancellor of Germany.

But when politicians reverse course and change their opinions, political pundits, critics and others often call them out for lack of consistency, and might label them a flip-flopper, U-turner or backflipper.

Republican presidential nominee Donald Trump has been criticized for changing his mind on on everything from immigration policy to abortion, depending on who he is talking to and when.

Likewise, Democratic presidential nominee Kamala Harris has been accused of reversing her stances on private health insurance, fracking and other issues in order to win new voters.

Trump’s running mate, JD Vance, has drastically changed his mind over the past few years, as well. Before Trump was elected president in 2016, Vance publicly called him an “idiot” and privately compared him to Adolf Hitler – before going on to accept Trump’s offer to run for office together eight years later.

At the start of Democratic vice presidential nominee Tim Walz’s political career in 2007, he received an endorsement from the National Rifle Association for his support of gun rights. But Walz had what he called a “reckoning” after the 2018 Parkland high school shooting in Florida. He went on to support and approve gun safety measures as Minnesota governor.

Some voters demand that politicans’ beliefs should be stagnant, as if they were preserved in amber.

The reality is, as much as people sometimes forget, politicians are humans, too. They have all the same strengths and flaws as the rest of us. When I teach a course on the American presidency every fall, I often point out that perspective can change depending on which side of the desk someone is sitting on in the president’s office.

Hundreds of years of flip-flopping

Thomas Jefferson, the third U.S. president from 1801 through 1809, was a huge advocate for limited government when he ran for office in 1800. Jefferson and his anti-federalist allies called sitting president John Adams at one point a “royalist.” Jefferson accused people in the Federalist Party, who wanted a strong national government, of trying to set up a monarchy in the United States.

Before Jefferson became president, he embraced the idea of a very small national government with restricted powers. He emphasized the importance of strong state power and a very limited national budget.

However, once he was elected president, he was given the opportunity to buy 530 million acres in North America from France, in what we now call the Louisiana Purchase. This doubled the size of the U.S. by adding land from the Mississippi River to the Rocky Mountains.

Jefferson bought this land without input from Congress, demonstrating a stark reversal of his previous policy that de-emphasized the federal government.

Jefferson was aware of this conundrum and, in a letter to American politician Levi Lincoln in 1803, wrote, “The less is said about any constitutional difficulty, the better: and that it will be desirable for Congress to do what is necessary in silence.”

Jefferson knew that he was flip-flopping, but he also believed the Louisiana Purchase was in the country’s best interest.

To tax or not to tax?

Nearly two centuries later, George H.W. Bush ran for president in 1988. During the Republican National Convention that year, Bush wanted to draw a clear line between himself and Michael Dukakis, his Democratic opponent.

Dukakis had said he would raise federal taxes as a last resort. And Bush wanted to shore up conservative support. During his acceptance speech, Bush uttered the now famous phrase, “Read my lips: no new taxes.”

Unfortunately for Bush, the economic climate was not on his side. A slowing economy meant that, as president, Bush was forced to raise taxes – or else enact massive budget cuts that would be unacceptable to the Democrats controlling the House and Senate.

Still, some Republicans felt betrayed by Bush’s reversal.

Bush’s flip-flop on taxes is considered a large contributing factor to his loss in 1992 when he ran for reelection.

I did, before I didn’t

The term “flip-flopping” reached new heights of popularity during the 2004 presidential election. Republican presidential nominee George W. Bush – son of George H.W. Bush – and others pegged the Democratic rival, John Kerry, as a flip-flopper to help discredit him.

“You get a little dizzy if you listen to John Kerry explain his recent position on any particular issue at the time,” said Jeb Bush, brother of George W. Bush, in 2004. “There really is a tale of two Kerrys.”

Bush and other Republicans used the term to paint Kerry as a person who shifted positions with the wind for political gain. In March 2004, Kerry memorably said that,, with respect to his Senate votes on additional spending on the military, “I actually did vote for the $87 billion before I voted against it.”

Kerry was attempting to explain that he voted for an earlier, Democratic-proposed version of a military appropriations bill that would have given money to U.S. operations in Iraq and Afghanistan, paid for by reducing tax cuts. But this measure was defeated, and so Kerry voted against a different, final version of the bill to demonstrate his opposition to then-president George W. Bush’s Iraq policy.

This convoluted phrase became the defining moment of Kerry’s campaign, which ended in defeat.

Flip-flopping today

Trump has flip-flopped on issues, from the innocuous to the important, throughout his political career and it has done little to erode support from his most ardent followers.

After years of declaring that mail-in ballots are crooked and fraudulent, Trump now embraces them as an electoral strategy in 2024. Trump also changed his political party affiliation multiple times, and has been a Republican, independent and Democrat before switching back to being a Republican a few years before his 2016 campaign.

When Trump was running for president, he heavily criticized Barack Obama for playing golf as president. Obama ultimately played about 105 rounds of golf in his first term. Trump went to a golf club 285 times in the same period and played golf at least 142 times.

And while in 2019 Harris, then running for president, said that she would support a ban on fracking, she now opposes doing so.

She also then supported a broad government-run health insurance program and proposed having “Medicare for all.” Harris’ campaign has said in 2024 that she will not push for this kind of government health insurance.

A political strategy

Flip-flopping is an easy slur to hurl at an opponent.

This can be a brilliant way to try to throw someone on the defensive while appearing to have clean hands yourself.

People evolve. Information changes. Hard choices have to be made for the good of the country. I think that we should all reserve the right to get smarter and, hopefully, better.

Shannon Bow O'Brien does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.