Tucker Carlson debated a New York City Democrat on what can be done to heal the deep and worsening political divide in America.

And he also tried to zero in on what he calls the one question on immigration that liberals will never answer. 

He talked to Mark Green, former NYC public advocate, who recently formed a group of 17 policy experts called the "Shadow Cabinet" to oppose and debunk "Trump's lies."

Carlson argued that the issue of illegal immigration and "sanctuary" policies shows the disconnect. 

He pointed out that leaders of so-called "sanctuary cities" are going a step further by defying federal law, essentially saying "we're our own country, we're not subject to the laws passed in Washington."

"That is something without recent precedent," said Carlson.

Green accused Carlson of exaggerating for "effect" on the issue, calling President Trump a "demagogue" who was elected thanks to FBI Director James Comey's actions and Russian interference.

"Come on, you're smarter than that. That's insane," Carlson answered.

He argued that Green was putting the problems of divisiveness "on display" by refusing to actually answer his questions.

Carlson then pressed Green for an answer on what can be done to address immigrants failing to "assimilate" into the country, thus deepening the divide.

"Newcomers to America should be taught what, in order to make them American? The language, the history, the culture? What are the core beliefs we need to inculcate in immigrants to keep this country united rather than divided?" he asked, later referring to it as "the one question on immigration that no liberal will answer."

Green countered by accusing Carlson of suggesting that the U.S. is being "overrun" by immigrants, arguing that refugees commit crimes at a lesser rate than Americans. 

Watch a clip above and the full debate below.

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