Democrats could have Mnuchin arrested if he refuses to hand over Trump's tax returns: MSNBC legal analyst
Treasury Secretary Steve Mnuchin poses with his wife Louise Linton while holding a sheet full of dollars (Twitter photo).

The Democratic battle to obtain President Donald Trump's tax returns is likely to be long and fierce. But at some point, said legal analyst Elie Mystal in his Friday appearance on MSNBC's "The Beat," the law will catch up to Treasury Secretary Steve Mnuchin if he refuses to comply with Congress.

"The administration has the authority to make it clear for us to see it, but Steve Mnuchin has a responsibility for Congress to see it," said Mystal. "It's the law ... he could be held in contempt of Congress if he doesn't follow the law."

"They could literally go over to his office and arrest him if he doesn't follow the law," said Mystal. "As complicated as tax laws are, this one is very clear: upon written request from the chairman of the Committee on Ways and Means, the chairman shall furnish such a committee with any return information supplied upon request. So that's as clear as it gets!"

Watch below: