They need a two-thirds vote in both the House of Representatives and the Senate; or a conventio called by Congress at the request of two-thirds of the state legislatures. Then it has to be ratified by the legislatures of three-quarters of the states.
Even if they managed a super majority on both sides of Congress for Trumplefuck, there's no way they're getting 38 States to agree to that.
Trump is ruling by executive order and no one is stopping him from doing any of it, constitutional or not.
He'll just issue an executive order to lower the threshold and at best that order gets challenged and goes to the SCOTUS, and we all know what will happen there.