U.S. Senator Elizabeth Warren on Thursday pressed the Obama administration to pledge to veto any annual budget measure that includes a Republican-backed, anti-transparency provision. In an interview with International Business Times, the Massachusetts Democrat said the White House should take a hard line against the provision, if the rider makes it into a year-end budget bill to fund the government.

The rider — which was inserted into last year's budget and which bans regulators from forcing companies to disclose their political spending — was preserved by GOP leaders in a temporary budget measure that will keep the government running until after the November election. Warren said she believes it must ultimately be removed in the final year-end spending measure that Congress is expected to consider this winter.

“Obviously this one is now done — we’ve got a continuing resolution that is going to hold up until the lame duck,” she told IBT. “But I would like to see the White House much more actively involved in the negotiations and tell the Republicans directly that the president will not sign a budget that includes a provision to protect dark money.”

Warren’s veto demand comes as cash floods into groups that do not have to disclose their donors. The nonpartisan Center for Responsive Politics reports that more than $73 million of such “dark money” has been spent during the current election cycle. A disclosure rule could force publicly traded companies to disclose how much dark money they are spending.

Last week, the Obama administration floated the possibility that the president could veto a budget bill because the GOP rider is in it — but the White House did not commit to such an action.

“I had an opportunity to talk with the president in the Oval Office about this proposal.  And after that conversation it's not at all clear to me that he is prepared to sign this bill,” said White House spokesman Josh Earnest. The president, Earnest said, is “concerned about the fact that the proposal includes a rider that would essentially protect the ability of special interests to funnel money into political campaigns without having to disclose it.”

Democrats have for years asked the Securities and Exchange Commission to enact a rule requiring corporations to disclose to shareholders precisely how they are spending company resources on political causes. Despite those calls, the Obama-appointed chairwoman of the commission, Mary Jo White, removed the proposal from the agency’s list of priorities in 2014.

The next year, with campaign cash pouring into the presidential primary contests, Republican lawmakers attached a rider to the annual federal budget that blocks the agency from spending any resources to implement a final spending disclosure rule. Republicans lawmakers have generally asserted that policing political spending is not the purview of the SEC.

“The role of the SEC is investor protection, not to engage in a political foray,” said U.S. Rep. Scott Garrett, a New Jersey Republican, in 2013 when the push for the rule was gaining momentum. This year, when a watchdog group filed a lawsuit to try to force the SEC to act, Republican senators filed an amicus brief decrying what they called a “lawless suggestion that an agency may plan, draft — and even ‘propose’ — a rule that it has no authority to issue.”

The GOP’s 2015 rider to block the SEC from acting only temporarily derailed the push for a spending disclosure rule. Earlier this year, Democratic senators sent a letter to the SEC advising the agency that it could still use resources to develop such a rule — and according to transparency groups, the agency has now received more than 1.2 million public comments in support of the proposal. In April, Warren and New York Democratic Sen. Charles Schumer temporarily stalled two Obama SEC nominees because, the lawmakers asserted, the prospective commissioners had not taken a clear position in support of a transparency rule. The pair also slammed White during a June appearance on Capitol Hill.

“Instead of making up work to help giant corporations, the SEC should do its job,” Warren said at the time. “A year ago I called your leadership at the SEC extremely disappointing, today I am more disappointed than ever.”

Schumer told White that by refusing to move a rule forward, “You’re hurting America.”