House Republicans cast the mayors of four major American cities as willful impediments to President Trump’s mass deportation agenda during a tense congressional hearing on Wednesday. But in doing so, Republicans also gave the leaders a national platform to passionately defend their cities’ policies and immigrants.

The hearing of the House Committee on Oversight and Government Reform, one of the most contentious on Capitol Hill, lasted nearly six hours and grew increasingly confrontational. Republicans accused the Democratic leaders of New York, Chicago, Denver and Boston of sheltering dangerous criminals, while several of the mayors pointed to inaction in Washington.

Many Republicans demanded yes or no answers to questions that were intended to force the mayors into stumbles that could hurt them with their constituents — and perhaps create a viral moment for members of Congress trying to bolster their reputations as standard bearers for the Trump administration.

Here are five takeaways from the hearing:

Republicans tried to pin migrant crimes on ‘sanctuary city’ policies.

House Republicans argued that officials in so-called sanctuary cities have refused to fully cooperate with federal immigration enforcement efforts, making them at least partly responsible when migrants commit violent crimes.

From the start of the hearing, the committee chairman, Representative James Comer of Kentucky, and many other Republicans, referred to cases of rape or murder involving unauthorized immigrants and asked each mayor if he or she would have handed the suspect over to Immigration and Customs Enforcement.