Most of the likely Republican presidential candidates are supportive of the National Security Agency's surveillance programs. But Americans who identify as Republican or lean that way appear to disagree.

That's according to a new survey from Pew Research, released on Monday, gauging post-Snowden attitudes on digital privacy and surveillance. Of respondents who were familiar with the NSA spying revelations, 70 percent of Republicans and those leaning Republican said they were losing confidence that the agency's surveillance programs served the public interest. Just 55 percent of Democrats and those leaning Democratic said they had lost faith.

Overall, 61 percent of respondents said they had become less confident that surveillance operations had served the public interest, while 37 percent registered that they had become more confident in the benefits of the programs.

The split is just one of several findings in the Pew survey, which measured how much the Snowden leaks, which began in June 2013, have changed how Americans try to protect their privacy online. Thirty percent of adults aware of the government-surveillance programs said they had taken at least one step to change how they communicate online—such as changing privacy settings on social media or avoiding certain words in online messages—although only 2 percent had adopted email encryption.

But the strong majority of GOP respondents who say they have lost confidence in the importance of the NSA's bulk collection of phone and Internet communications is likely a boon to the expected presidential campaigns of Sens. Rand Paul and Ted Cruz. Their anti-NSA positions put both in the minority within the crowded GOP field, which features several contenders who ascribe to the party's more traditional defense-hawk roots.

The survey may also suggest that Senate Republicans are out of step with the majority of their base voters on government surveillance.

In November, legislation intended to curtail the NSA's surveillance of U.S. phone records narrowly died in the Senate. The bill, known as the USA Freedom Act, fell two votes short of clearing the 60-vote filibuster-proof threshold needed to advance. Although every Democrat except Sen. Bill Nelson backed the Freedom Act, just four Republicans—including Cruz—crossed the aisle.

At the time, then-Minority Leader Mitch McConnell whipped his caucus to oppose the measure, on grounds that its passage could help terrorists kill Americans. Because of the McConnell-led filibuster, the Republican takeover of the Senate this year has been widely viewed as an additional roadblock for NSA reform.

Many of the GOP's expected White House contenders have also taken positions in defense of the NSA. In a major foreign policy speech last month, former Florida Gov. Jeb Bush said mass surveillance was "hugely important." Sen. Marco Rubio, also from Florida, recently called for apermanent extension of the USA Patriot Act provisions that provide the legal authority for the NSA's bulk collection of Americans' call data. New Jersey Gov. Chris Christie has admonished NSA critics by telling them to sit down with the families of the victims of Sept. 11, 2001.

But Paul has made his loud opposition to government surveillance—he filed a class-action lawsuit against the NSA in 2014—a central plank of his expected presidential campaign. Appearing at the SXSW technology conference in Austin over the weekend, Paul told a crowd, "I'm the only candidate who thinks that the NSA program on bulk collection of your phone records should be shut down."

Cruz, meanwhile, has also emerged as a a 2016 contender pushing for NSA reform—though not as sweeping as the kind Paul advocates. Democratic Sen. Patrick Leahy, who authored the Freedom Act, leaned on Cruz to cajole his Republican colleagues to support the bill in the name of protecting constitutional liberties. GOP Sens. Mike Lee, Dean Heller, and Lisa Murkowski joined Cruz, but Paul issued a crucial no vote, saying he couldn't support anything that reauthorizes the Patriot Act.

Hillary Clinton, the presumptive Democratic front-runner for the White House, has shied awayfrom weighing in specifically on the NSA's controversial programs, instead offering vague platitudes about the need to balance privacy and national security.

NSA surveillance is expected to again emerge as contentious policy debate in the coming months, because core provisions of the Patriot Act are due to sunset on June 1. That looming deadline will give Paul and Cruz another chance to tout their anti-spying credentials as 2016 campaign gains more attention.

Among Pew's other findings, Americans were strongly divided on whether courts do a good job of balancing the needs of law enforcement and intelligence agencies with privacy rights. Forty-eight percent said judges did a good balancing job, while 49 percent said they did not.

Fifty-seven percent of adults said it was unacceptable for the government to monitor the digital communications of U.S. citizens, while 52 percent said they were either "very concerned" or "somewhat concerned" about that kind of surveillance. Forty-six percent said they were "not very concerned" or "not at all concerned" about surveillance.

Pew surveyed 475 adults between Nov. 26, 2014, and Jan. 3, 2015. Twenty-four percent of respondents identified as Republican, 36 percent said they were Democrats, and 33 percent identified as independent.