New Jersey Governor Chris Christie said he’d back Donald Trump again if he runs for a second term, but he isn’t sure the president would want another four years in the White House.

“If he runs again I would support him, yes, but I’m not so sure what would happen,” Christie said during an interview Friday on NBC’s “Today” show. “Four years is a long time, and especially for someone who has not spent a lifetime in politics, so I think those years affect him differently, so I’m sure the president will make whatever decision is best for him and his family and the country.”

Trump has already begun raising money for a re-election campaign. He’s taken in $22 million for his campaign, including $14.2 million that came via his joint fundraising committees, which also benefit the Republican National Committee. Overall, Trump’s three committees have raised $37.6 million, according to Federal Election Commission records.