I don't think the payroll tax is anything but pandering.
In all seriousness the stock market is not the economy and let it shave off some of the fat it has been building up for years. it cannot keep going up unless it retracts and consolidates so all this panic is just Trump worried about how it reflects on him (market up all his doing, market down blame the Dems).
Payroll tax is just going to put a penny or two of money in the billion dollar economy. Just leave shit alone and it will work itself out.