The Trump administration is pleading with Congress for broad authority to exempt certain countries and entities from a robust regime sanctions targeting Russia—but lawmakers, mostly at the behest of the Republican majority, aren’t budging.

“The administration is not going to get the broad waiver that it wants,” said a congressional aide with direct knowledge of the matter. “The administration understands it is not going to get what it is asking for.”

Instead, three sources involved in the negotiations say, Congress is moving closer to creating a set of guidelines for the administration to use before it can authorize exemptions to the tough sanctions—signalling that lawmakers are not comfortable with Trump administration officials making those decisions on their own.

In the months following President Donald Trump’s inauguration, the House and Senate overwhelmingly passed a tough, mandatory sanctions package aimed at punishing Russia for election-meddling and its incursions into eastern Europe and the Middle East. The sanctions targeted Russia’s defense and intelligence sectors, and the legislation removed the administration’s ability to unilaterally water down or weaken the sanctions. (Despite that strong language, the administration has not fully implemented all of the penalties.)

But earlier this year, the Pentagon asked Congress for sweeping authority to waive sanctions against U.S. strategic and military allies—like India, Indonesia and Vietnam—that are still purchasing Russian weapons systems. Under the legislation, the Countering America’s Adversaries Through Sanctions Act (CAATSA), any country or entity purchasing Russian weapons is subject to U.S. sanctions—the goal being to isolate Russia strategically and financially.

The bill was crafted such that it gave the Trump administration virtually no wiggle room in implementing the sanctions, and many of the lawmakers who put the bill together appear unwilling to cede any of that power to the White House.

“If you’re going to sanctions Russia and then you start creating waivers, then you undermine the very essence of those sanctions,” Sen. Bob Menendez (D-N.J.), the top Democrat on the Senate Foreign Relations Committee, told The Daily Beast. “And that’s a slippery slope—which countries do you give it to, which ones do you not?”

Those strategic allies argue that they need to continue purchasing Russian weapons in order to meet commitments to replace and revamp their existing military infrastructure, which is Russian-made. As a result, Defense Secretary James Mattis has asked Congress for relief.

The issue is a major sticking point in the ongoing negotiations between the House and Senate on the final version of the National Defense Authorization Act (NDAA), the annual defense appropriations bill. Rep. Adam Smith (D-WA), the top Democrat on the House Armed Services Committee, told The Daily Beast that lawmakers are likely to agree on a tailored waiver process that creates allows Congress, not the Trump administration, to set the guidelines.

“The Pentagon has made a very strong case that we need India, we want to build a relationship there and not cut it off,” Smith said in an interview. “We’re trying to craft a waiver that is not blanket, which says: you have to meet certain criteria in order to qualify for the waiver.”

In response to Mattis’ request, some lawmakers have said Congress should grant the Pentagon specific waivers that would exempt those countries from U.S. sanctions—rather than giving the administration broad authority to make those decisions on its own. They argue that sanctioning India would push that country more toward Russia and away, strategically, from the U.S.

“If we want to encourage countries like India to partner with the United States of America, the world’s largest democracy and world’s oldest democracy, then we ought to be all about encouraging that movement toward us and away from the Russian federation,” Senate Minority Whip John Cornyn (R-TX) said on Thursday, referencing India’s desire to buy a missile defense system, known as the S-400, from Russia.

But other lawmakers argue that India and other nations had ample time to wind down their relationships with Russian weapons manufacturers. They note that the legislation already includes built-in waivers for countries and entities which prove that they are taking steps to wind down their transactions with the designated Russian firms.

Moreover, they don’t trust the Trump administration with such broad power to designate exemptions, especially in light of the president’s apparent dismissal earlier this week of U.S. intelligence agencies’ assessments on Russian election-meddling.

“Countries have been put on notice for a long time. Congress passed this bill last year. There were alternatives available. They should’ve acted that way. And we should not be providing any weakness to our resolve against Russia. The Trump administration has already shown too much weakness, and we certainly don’t want to see Congress provide any waivers,” Sen. Ben Cardin (D-MD), a senior member of the Senate Foreign Relations Committee, said in an interview.

“I certainly oppose giving the president that authority. That was one of the reasons for CAATSA—to take that away from the president,” Cardin added.

Sens. Jim Inhofe (R-OK)—who is taking Sen. John McCain’s (R-AZ) place as chairman of the Senate Armed Services Committee while McCain remains at home in Arizona for cancer treatment—and his Democratic counterpart, Sen. Jack Reed (D-R.I.), have shied away from commenting on the waiver issues while the final NDAA bill is being put together.

The closed-door and sometimes heated negotiations between Congress and the Pentagon come as lawmakers are considering enacting even more sanctions targeting Moscow in advance of the 2018 midterm elections. American intelligence chiefs have said that Russia continues to target U.S. elections, but Trump on Wednesday appeared to contradict that assessment. (The White House later said the president was not answering that question.)

Lawmakers say that despite Trump’s posture, they are aiming to resolve the waiver issues before it balloons into a larger crisis. After all, just this week, it was revealed that the Philippines is seeking to buy RPG-7B rocket propelled grenade launchers from a Russian firm.