President Trump said Friday morning that if Vice President Pence runs for president in 2024, he wouldn’t automatically have his endorsement.

The president was asked the hypothetical during a wide-ranging interview on “Fox & Friends.”

“You’re talking about a long time. You can’t put me in that position,” Trump said, adding that Pence would have his “strong consideration.”

Whether Trump wins reelection in 2020, there will be a long list of Republicans vying for the White House four years later. While the sitting vice president is often considered the heir apparent, there are several other big-name Republicans who could edge Pence out, such as Sen. Marco Rubio (Fla.), former U.N. ambassador Nikki Haley and Secretary of State Mike Pompeo.

Pence has been extremely loyal to Trump throughout their tenure together, but the vice president may not be considered the strongest choice to motivate the Trump base even after eight years at the president’s side.

Though it probably stings for Pence that Trump wouldn’t automatically endorse him, it’s been nearly 20 years since the sitting vice president, then Al Gore, was the automatic front-runner.

Then, after eight years as George W. Bush’s vice president, Richard B. Cheney did not seek the nomination. After eight years of Barack Obama’s presidency, it was Hillary Clinton and not Joe Biden who was expected to take over.

When Biden was still considering running in 2016, Obama was asked in early 2015 whom he’d choose between his vice president and Clinton.

“I love ’em both. Good try,” he said.

Now, even with Biden leading a very crowded pack of Democrats vying to take on Trump in 2020, Obama has not given anyone his support.

But Biden is using his time at Obama’s side both in policy and as friends as a campaign advantage.

Even if Pence doesn’t win Trump’s endorsement in 2024, he’d likely do the same.