 In October 2017, Mast voted against the original version of the Tax Cuts and Jobs Act of 2017 due to "out of control" federal spending, fear of the national debt growing, and a desire to see lower tax rates with loopholes closed.In December 2017, he voted in favor of the final version of the bill.He says the bill "provides a lot of confidence to a lot of people" and is "a great moment for our country and our community".