Gov. Dannel P. Malloy of Connecticut on Wednesday personally welcomed a refugee family from Syria who had been diverted from Indianapolis to New Haven.

Meanwhile in New Jersey, Gov. Chris Christie, a Republican, sent a letter to President Obama saying he was directing his state’s Department of Human Services not to participate in the resettlement of Syrian refugees.

On Wednesday, the fate of Syrian refugees in the United States fully erupted into a fight over states’ rights, even though governors and other local officials hold no legal role in the federal program that was authorized by the 1980 Refugee Act.

More than 30 governors have come out in recent days to say that their states will not accept refugees from Syria, even as Gov. Andrew M. Cuomo of New York and Governor Malloy, both Democrats, remained staunch in their commitment to take refugees.

A State Department spokeswoman said that it “has no plans to curtail resettlement in any of the 180 communities that have committed to welcoming refugees” despite what state leaders were saying.

For immigration lawyers and constitutional scholars, governors’ threats to bar Syrian refugees from their states and to cut them off from state resources, as the Republican governor of Indiana suggested, struck them as unconstitutional.

“The Supreme Court for more than 100 years has been very clear that on matters of immigration the nation has to speak with a single voice,” said Stephen Legomsky, a former general counsel for United States Citizenship and Immigration Services who is currently a professor at Washington University School of Law. “It shouldn’t be up to one state to decide what U.S. foreign policy may be.”

Were state governments to withhold services only to Syrian refugees who received federal money, he said, that would seem to violate the 14th Amendment ensuring equal protection of the law.