eliminating the payroll tax is something i strongly disagree with trump about. thankfully, he couldn't really do it - not without congress, anyways.
it's not a question of how you pay for it, in the end, it's a question of who owns the money. even if the next ten administrations pay for it from general revenue, it's still shifting ownership of the fund from workers to government, and that must be resisted in principle.
we had a court case up in canada years ago, when the liberals (under paul martin) actually dipped into the fund to pay down the debt, which was horrific in principle - they literally took money from workers' pensions and destroyed it, by cashing it in at the bank. horrific. the ensuing court case ensured they can never do that again.
i would expect a similar battle in the end, but it opens up a valid question: should this system be reformed to ensure that politicians cannot touch it? maybe spun off or something?