In President Donald Trump's former life as a casino owner, he might have cheered this week's ruling from the Supreme Court that struck down a federal law that barred every state but Nevada from allowing betting on most sporting events.
But the Trump administration opposed the outcome reached by the high court at least in part because it could signal trouble in its legal fight against so-called sanctuary states and cities. Seven of the nine justices - five conservatives and two liberals - backed a robust reading of the Constitution's 10th Amendment and a limit on the federal government's power to force the states go along with Washington's wishes.
The federal anti-gambling law is unconstitutional because "it unequivocally dictates what a state legislature may and may not do," Justice Samuel Alito wrote in his majority opinion. "It's as if federal officers were installed in state legislative chambers and were armed with the authority to stop legislators from voting on any offending proposals."
There is a direct link between the court's decision Monday in the sports betting case and the administration's effort to punish local governments that resist Trump's immigration enforcement policies, several legal commentators said.
"The court ruled definitively that the federal government can't force states to enforce federal law. In the immigration context, this means it can't require state or local officials to cooperate with federal immigration authorities," said Ilya Shapiro, a senior fellow in constitutional studies at the libertarian Cato Institute.
Omar Jadwat, director of the ACLU's immigrants' rights project, said the ruling reinforced decisions from the 1990s, including one that struck down part of a federal gun control law that required local police to determine if buyers were fit to own handguns.
"It reiterates that the real thrust of the 10th Amendment and the principles of law in this area is that the fed government can't tell the states or cities how to legislate," Jadwat said. The amendment says that powers not specifically given to the federal government belong to the states.
The gun law decision split the court's conservatives and liberals in 1997, in keeping with conservatives' complaints about the federal government's overreach and the importance of states' rights. But on Monday, Justices Stephen Breyer and Elena Kagan joined their more conservative colleagues.
The Justice Department declined to comment on the decision, but it had called on the court to uphold the federal law at issue - the department's usual practice when federal laws are challenged - by arguing that there was no constitutional violation.
In the most recent ruling about sanctuary cities, the federal appeals court in Chicago held last month that the federal government cannot withhold public safety grants from cities that won't go along with Trump's immigration enforcement policies.
In lawsuits challenging the administration, cities argue that turning local police authorities into immigration officers erodes trust with minority communities and discourages residents from reporting crime. The administration says sanctuary jurisdictions allow dangerous criminals back on the street.
The administration's efforts to crack down on places that don't comply with immigration authorities have taken several forms. Trump issued an executive order aimed at withholding federal money from recalcitrant jurisdictions. The administration also has sued California over three laws aimed at protecting immigrants in the country illegally.
