An effort to slap new financial penalties on Russia ahead of the midterms is facing pushback from Senate Republicans who question whether that's the best approach.

Lawmakers on both sides of the aisle are under pressure to act amid growing concern that Moscow is trying to influence the November elections, with control of Congress hanging in the balance.

President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE’s rhetoric in Helsinki, more indictments in special counsel Robert Mueller Robert (Bob) MuellerCNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting The Hill's 12:30 Report: New Hampshire fallout MORE’s probe and reports of Russian hacking efforts against Democratic senators have increased scrutiny on what action, if any, Congress will take to respond.

But GOP senators are becoming increasingly skeptical that passing a new bill — roughly a year after Congress imposed stiff penalties on Moscow — will be enough to deter Russian President Vladimir Putin from interfering with congressional campaigns. ADVERTISEMENT

“Obviously what we want is a change in behavior, right?” said Sen. Bob Corker Robert (Bob) Phillips CorkerHas Congress captured Russia policy? Tennessee primary battle turns nasty for Republicans Cheney clashes with Trump MORE (R-Tenn.), the chairman of the Foreign Relations Committee. “We’ve inflicted a lot of pain but thus far there’s been no change in behavior.”

Senators emphasize that while they want to prevent Russia from interfering in U.S. elections, they aren't sure how to accomplish that. They’re also questioning if sanctions legislation should be the only option for the U.S.

“I think we need to increase our pressure on Putin and those around him to modify behavior,” said Sen. Jerry Moran Gerald (Jerry) MoranLobbying world This World Suicide Prevention Day, let's recommit to protecting the lives of our veterans Hillicon Valley: Zuckerberg acknowledges failure to take down Kenosha military group despite warnings | Election officials push back against concerns over mail-in voting, drop boxes MORE (R-Kan.).

“But are there other tools that we have besides sanctions that also could be included in that?” he said, pointing to export controls and restrictions on U.S. business investments.

Sen. Mike Rounds Marion (Mike) Michael RoundsDemocrats call for declassifying election threats after briefing by Trump officials The Hill's Morning Report - Sponsored by Facebook - GOP closes ranks to fill SCOTUS vacancy by November Senate GOP sees early Supreme Court vote as political booster shot MORE (R-S.D.) added that lawmakers are trying to figure out the “appropriate tactics” to make Russia reconsider its election meddling efforts.

The Foreign Relations Committee and Senate Banking Committee are slated to hold hearings on issues ranging from NATO to broader Russian policy. But those hearings won’t take place until after senators return from a two-week recess, meaning any legislative action will likely be pushed back to the fall, even closer to the midterms.

Members of the Banking Committee were briefed this past week by administration officials on the implementation and effectiveness of the 2017 Countering America's Adversaries Through Sanctions Act, which could provide guidance for new measures.

But Sen. Mike Crapo Michael (Mike) Dean CrapoBottom line Davis: The Hall of Shame for GOP senators who remain silent on Donald Trump Top GOP senator urges agencies to protect renters, banks amid coronavirus aid negotiations MORE (R-Idaho) — the chairman of the Banking Committee, which has jurisdiction over sanctions — is not convinced that new legislation is the way to go.

“Well, I don’t know, I guess I’m not going to register an opinion on that yet because right now we need to do the investigative work and get exactly what the options are,” Crapo said when asked if there was momentum behind passing legislation.

Fellow committee member Sen. Tim Scott Timothy (Tim) Eugene ScottAuthor Ryan Girdusky: RNC worked best when highlighting 'regular people' as opposed to 'standard Republicans' Now is the time to renew our focus on students and their futures GOP lobbyists pleasantly surprised by Republican convention MORE (R-S.C.) said he would support additional sanctions legislation if it would be “helpful,” but said it’s unclear yet if that’s the case.

“It’s hard to tell,” he said. “I think the question is: How do you have the ultimate impact of changing Russia’s behavior to the level that we would find meaningful?”

“I’m not sure what additional legislative vehicles would get us there,” he added.

Talk of new legislation on Capitol Hill comes as Trump has repeatedly cast doubt on whether Russia interfered in the 2016 election, despite findings from both the U.S. intelligence community and the Senate Intelligence Committee.

Hours after the administration’s top five national security officials spoke at a White House press briefing — part of an effort to show the administration is confronting Russia — Trump decried the “Russian hoax” during a rally in Pennsylvania and touted his “great meeting” with Putin.

Any new legislation would likely have to overcome pushback from Trump’s staunchest congressional allies, as well as a White House that has been wary of efforts by Congress to insert itself into foreign policy. Legislation proponents also face a tight calendar if they want to get a bill to Trump’s desk before the midterms: The House is out until September and expected to leave town again for the back half of October.

Meanwhile, there are growing concerns on and off Capitol Hill about Russia’s continued effort to interfere in U.S. policy.

Sen. Claire McCaskill Claire Conner McCaskillMomentum growing among Republicans for Supreme Court vote before Election Day Democratic-linked group runs ads in Kansas GOP Senate primary Trump mocked for low attendance at rally MORE (D-Mo.), one of the most vulnerable Democrats up for reelection this year, confirmed that Russia had attempted to hack her campaign. Facebook announced late last month that it had removed 32 pages and accounts involved in "inauthentic behavior.”

“Some feel that we as a society are sitting in a burning room, calmly drinking a cup of coffee, telling ourselves, 'This is fine,' ” Sen. Richard Burr Richard Mauze BurrHillicon Valley: Subpoenas for Facebook, Google and Twitter on the cards | Wray rebuffs mail-in voting conspiracies | Reps. raise mass surveillance concerns Bipartisan representatives demand answers on expired surveillance programs Rep. Mark Walker says he's been contacted about Liberty University vacancy MORE (R-N.C.), the chairman of the Senate Intelligence Committee, said during a hearing this past week. “That's not fine.”

But even as frustration with Russian meddling has simmered, smaller efforts in the Senate have been shot down.

Republicans twice blocked a bipartisan resolution to support the intelligence community’s findings that Russia interfered in the 2016 election, with GOP lawmakers calling it a distraction. They also rejected additional election security funding, saying states hadn’t yet spent the initial $380 million.

Republican leadership, including House Speaker Paul Ryan Paul Davis RyanKenosha will be a good bellwether in 2020 At indoor rally, Pence says election runs through Wisconsin Juan Williams: Breaking down the debates MORE (R-Wis.) and Senate Majority Leader Mitch McConnell Addison (Mitch) Mitchell McConnellTrump 'no longer angry' at Romney because of Supreme Court stance On The Money: Anxious Democrats push for vote on COVID-19 aid | Pelosi, Mnuchin ready to restart talks | Weekly jobless claims increase | Senate treads close to shutdown deadline The Hill's Campaign Report: Trump faces backlash after not committing to peaceful transition of power MORE (R-Ky.), have left the door open to passing new sanctions legislation if the committees responsible for vetting a bill sign off on it.

A bipartisan group of senators introduced wide-ranging legislation on Friday that GOP Sen. Lindsey Graham Lindsey Olin GrahamSteele Dossier sub-source was subject of FBI counterintelligence probe Hillicon Valley: Subpoenas for Facebook, Google and Twitter on the cards | Wray rebuffs mail-in voting conspiracies | Reps. raise mass surveillance concerns Key Democrat opposes GOP Section 230 subpoena for Facebook, Twitter, Google MORE (S.C.), who helped crafted the proposal, termed the “sanctions bill from hell.”

In addition to new sanctions, the bill would require a two-thirds vote in the Senate if Trump wanted to withdraw from NATO, and the State Department would have to determine if Russia is a state sponsor of terrorism.

Negotiations continue around a bipartisan bill from Sens. Marco Rubio Marco Antonio RubioGOP lawmakers distance themselves from Trump comments on transfer of power McConnell pushes back on Trump: 'There will be an orderly transition' Graham vows GOP will accept election results after Trump comments MORE (R-Fla.) and Chris Van Hollen Christopher (Chris) Van HollenCongress must finish work on popular conservation bill before time runs out Democrats fear Russia interference could spoil bid to retake Senate Mid-Atlantic states sue EPA over Chesapeake Bay pollution MORE (D-Md.) that would slap new penalties on Russia if, in the future, the director of national intelligence determines Moscow is meddling in elections.

Rubio — who has said there are parts of the bill that need to be “altered and refined” — told reporters that he has heard some “well-founded” concerns from colleagues about the bill, including the potential for sanctions to have “unintended consequences” or the director of national intelligence possibly having unilateral authority to impose new sanctions.

When asked separately about ongoing discussions, Rubio said the talks were not about watering down the bill but “largely about picking the right” sanctions.

Corker told The Hill that discussions were underway with Rubio, Van Hollen, Crapo and their staffs to “try to make sure the legislation that is crafted has the desired outcome.”

“What we would hope, and I’m not sure we will be able to get there, but by the time we come back from recess I’m hoping to be able to sit down and be in a really good place as it relates to what we think are the kinds of things that might generate the desired outcome,” Corker said.

Corker told reporters last month that he believed Congress would pass new Russia legislation. But since then, he’s not so sure.

“I don’t know. That’s the process we’re going through right now,” he told The Hill on Wednesday. “We’ve put a lot of sanctions in place. It’s created a lot of pain. But the Russians are still doing the same things they’ve been doing, right?”