A leading progressive group emailed all House and Senate Democratic staff Monday evening to urge them to reject the fiscal deal now coming into focus because it would reportedly extend the Bush income tax cuts up to the $400,000 threshold, not to the $250,000 threshold long pushed by Democrats.

The higher threshold “violates progressive principles” because it means billions of dollars will have to come out of the pockets of working-class families to pay for a tax break for wealthy people (i.e., those in the $250,000-$400,000 bracket), reads the email from Adam Green and Stephanie Taylor, co-founders of the Progressive Change Campaign Committee.

Here’s their full email:

Hill friends … On behalf of nearly a million progressives nationwide, we wanted to emphasize that this is a moment to stand on principle.There has always been room for negotiation, but throughout this debate progressives have had 2 bright-line positions: Tax rates on those making $250,000 must go up to at least the Clinton rates and there must be no cuts to Medicare, Medicaid, and Social Security benefits.