The White House is now openly declaring that Senate Democrats who support new sanctions against Iran are itching for war, but their campaign to pressure their own party members has been going on for months and has done little to dissuade Democrats from supporting sanctions.

The White House brought their fight with Congressional Democrats out in the open Thursday evening when National Security Staff member Bernadette Meehan sent an incendiary statement lashing out at pro-sanctions Democrats to a select group of reporters, accusing them of being in favor of a strike on Iran.

“If certain members of Congress want the United States to take military action, they should be up front with the American public and say so,” said Meehan. “Otherwise, it’s not clear why any member of Congress would support a bill that possibly closes the door on diplomacy and makes it more likely that the United States will have to choose between military options or allowing Iran’s nuclear program to proceed.”

Meehan’s statement was issued the same day Senate Foreign Relations Committee Chairman Robert Menendez (D-NJ) published a Washington Post op-ed arguing in favor of legislation that would spell out Congressional parameters for a final nuclear deal with Iran and propose new sanctions that would take effect if diplomacy falls through.

In the op-ed Menendez called his legislation a “diplomatic insurance policy” and “an act of reasonable pragmatism.”

But the White House both privately and publicly has warned Democratic lawmakers that supporting the Menendez legislation could mean they will be blamed if the negotiations collapse, according to both administration officials and Congressional staffers engaged in the legislative process.

The message from the White House echoes warnings from Iran’s foreign minister, Javad Zarif, who last month said new sanctions in Congress would derail the interim agreement he signed at the end of November. Senior Obama administration officials themselves have warned privately that even the introduction of the new sanctions measure, let alone its passage, jeopardized the new round of talks in Geneva.

But the White House’s warnings have had little effect. Menendez and Sen. Mark Kirk introduced their bill on Dec. 16 with 13 Republican co-sponsors and 14 Democratic co-sponsors. The bill now has 59 co-sponsors, including 16 Democrats.

White House Press Secretary Jay Carney declined Friday to back down from Meehan’s characterization of pro-sanctions Democrats as warmongers.

“I don’t know every one of 100 senators what their personal views on, on whether or not military force ought to be used in Iran, so I can’t give a blanket statement about how they all feel,” he said. “What I do know is, when it comes to Senator Menendez and all of the partners who have assisted this administration over the years in building a sanctions regime is that we share a common goal, which is to deprive Iran of the opportunity of acquiring a nuclear weapon and to do so through negotiations. That’s why we built the sanctions regime.”

That explanation glosses over the fact that the Obama administration worked against several sanctions measures Congress has passed in recent years, despite claiming credit for those sanctions after the fact.

Regardless, both Democrats who support the administration and those who support Menendez told The Daily Beast that the White House’s tactic of going after their own party’s legislators is over-the-top and ineffective, alienating allies, creating bad will on Capitol Hill, and wasting political capital the administration may need on this issue down the road.

“The White House has clearly overreached in calling Democratic supporters of the Menendez-Kirk bill warmongers,” one senior Democratic Congressional aide said. “These are Democrats, some who have been in public service for decades and have long supported increasing sanctions against Iran. It’s just not credible and not helpful for them to use such extreme language when it’s clearly not true.”

Even those who support the administration’s overall position on Iran sanctions say the White House’s tactics are backfiring. Trita Parsi, the executive director of the National Iranian American Council, which opposes new sanctions legislation, said that the White House doesn’t appreciate that to oppose the Menendez-Kirk bill is a risky decision for Democrats because it puts them at odds with the pro-Israel lobby and many of their constituents.

“The approach of the White House towards Congress, particularly towards allies, is not one that tends to build political capital and as long as they continue to use that approach, there is going to continue to be unnecessary resistance,” said Parsi. “The sense in Congress is that the White House is asking them for political cover but not giving them political cover. There’s a widespread perception that there’s no reciprocity.”

The White House first hinted that new sanctions will lead to war on Nov. 12, when Carney rejected the idea of new sanctions legislation by saying, “The American people do not want a march to war.”

Menendez personally told Obama such rhetoric was unhelpful in a 30-minute meeting on Dec. 11 at the White House. Menendez conveyed to Obama that the White House characterization of the bill as a march to war was inconsistent with the objective of finding a peaceful solution to the Iran crisis, said a source briefing on the meeting.

The Obama administration pulled out many stops at the time to dissuade Menendez from introducing his sanctions legislation. Senior administration officials, including White House Chief of Staff Denis McDonough and Undersecretary of State Wendy Sherman, in November and December made personal phone calls to Senate Democrats claiming that Iran would walk away from the negotiations if Menendez introduced his sanctions bill.

“Wendy Sherman and Dennis McDonough burned up some credibility last month when they told Senators that the mere introduction of the legislation would kill the Iran talks,” a senior Senate aide said. “They were fear mongering at the end of session telling Senators that Iran would walk away if the Senate merely introduced the legislation. It didn’t happen.”

So far, the talks have not ended even though Menendez introduced his legislation nearly a month ago. Indeed experts point out that the one time Iranian officials walked away from the implementation talks last month, it was in response to the Treasury Department’s designation of several Iranian companies for sanctions, not in response to the actions of Congress.

“If the Iranians walk away over this bill, the blame is on the Iranians, not Bob Menendez, and we should question their intentions from the beginning. If the Iranians walk away over the enforcement of existing sanctions, would that be the Obama administration’s fault?” asked Mark Dubowitz, executive director of the Foundation for the Defense of Democracy, a group that supports the sanctions bill.

Some senior Democrats have sided with the White House. Democratic National Committee Chairwoman Debbie Wasserman Schultz was reported to be working against the introduction of a companion to the Menendez-Kirk legislation in the House. Her spokeswoman, Mara Sloan, told The Daily Beast that Wasserman Schultz was not working against introducing Iran legislation, but she does support holding off on new sanctions until the diplomacy plays out.

“The Congresswoman is confident based on the administration’s words and actions that they are not going to do anything that is not in our nation’s and Israel’s long term security interest. We need to give that a chance to work,” said Sloan.

Eli Lake contributed to this report.