Senator Elizabeth Warren told NBC News Tuesday night that she will not vote for a newly-introduced bipartisan bill that would enshrine federal abortion protections after the Supreme Court’s recent ruling overturning Roe v. Wade, a tough blow to the nascent effort that shows it would lack the crucial support of all 50 Democratic senators.

“The Kaine-Collins bill does not codify Roe,” she said plainly, saying “no” she wouldn’t vote for it. Pressed on if this was a question of letting the perfect be the enemy of the good on this, she said “the problem here is this bill is not an obvious improvement over where we stand right now.”

Warren has been a leading agitator for action on the reproductive rights front, prior to and certainly after the Dobbs v. Jackson Women’s Health decision, pressing the administration to do more and urging action on data privacy protections, among other things.