The White House wants to expand on ratings-based reward programs already in place, although it hasn't said exactly how.
The budget proposal shows 62 federal programs would be eliminated through zero funding.
Higher required contributions toward retirement, lower benefits again proposed.
Labor leaders say pay-for-performance allows discrimination and makes it easier to diminish federal pay.
The administration is roundly rejecting the idea of price setting for pharmaceutical products.
As GOP lawmakers prepare to pass tax plans that expand the deficit, the trio blasts “a broken budget process” that could upend military planning.
Democrats said they planned to focus on four key tax-reform topics: tax cuts for the wealthy, tax increases for the middle class, reductions to Medicare and Medicaid spending and increases to the budget deficit.
The meeting will come as the president tries to gain support for a tax cut plan.
A growing number of senators want a health-care measure attached to the 2018 budget bill, threatening not only its passage, but also the chances for a tax overhaul.