It's hard for anyone -- let alone a former president -- to visit Liberty University these days without mentioning President Donald Trump.

Sure enough, former President Jimmy Carter opened his recent Liberty commencement address with a quip linked to Trump's claims that his inauguration crowd was as large, or larger, than that of President Barack Obama.

The set-up: Trump addressed the school's 2017 graduates.

"This is a wonderful crowd," said Carter, after being introduced by Liberty President Jerry Falwell, Jr. "Jerry told me … that it's even bigger -- I hate to say this -- than it was last year." With a slight grin, he added: "I don't know if President Trump would admit that or not."

The crowd laughed, and some people cheered. Carter avoided any further Trump references -- at least by name.

The key to this day was that Carter and Falwell treated each other with respect, and even affection, setting the tone for an encounter between the evangelical left and right. In 2015, Falwell also made headlines by inviting Sen. Bernie Sanders to speak on campus.

Calling the 93-year-old Carter the "world's most famous Sunday school teacher," Falwell praised his declaration of born-again Christian faith while in public life and his legacy, as an ex-president, of serving others. Liberty's leader stressed that Carter showed political courage, and paid a high price among Democrats, when he signed the Hyde Amendment banning the use of federal funds to pay for most abortions.

"The longer I live, the more I want to know about a person, and to give my political support to a person," said Falwell. "Policies are important. But candidates lie about their policies all the time in order to get elected. The same elite establishment that Jesus condemned remains the real enemy today."

Carter's visit, he added, was an example of Christians "uniting … on issues where they agree, rather than fighting about issues where they disagree."