Nashua, New Hampshire (CNN)Leading Republican presidential contenders aren't shying away from proposals to overhaul Social Security and Medicare—once considered untouchable third rails of American politics.
Chris Christie, Marco Rubio and Jeb Bush all told audiences at the Republican Leadership Summit in New Hampshire this week that the United States must rein in spending on those programs, largely by raising the minimum age of eligibility.
Their comments set up a potential clash with Democratic front-runner Hillary Clinton—and pose a fresh test of whether younger generations are willing to side with a party that proposes big changes to decades-old programs.
Christie holds New Hampshire town hall 02:47
"There is no political advantage to talking about those issues," Christie said earlier this week. "The reason you talk about them is because you want to really make suggestions that will help solve the problems that our country confronts."
Christie, the New Jersey governor who's flagging in the polls, ushered in the debate when he unveiled a proposal to overhaul entitlement programs that's meant to be a centerpiece of his campaign.
It's an effort to play up Christie's brusque, straight-talking style—on display as he honed in on the issue at two town hall meetings he held in New Hampshire, insisting that other contenders' claims that they'd beef up national security are nothing but talk until they address Social Security and Medicare, too.
His means-testing proposal would phase out Social Security benefits for those earning more than $80,000 in annual retirement income, and eliminate them for those who bring in more than $200,000. He'd raise the retirement age to 69 for Social Security and 67 for Medicare, and impose a similar sliding scale for the health insurance program's benefits, requiring wealthier seniors to cover more of their premiums.
Rubio, the Florida senator, was asked about Christie's proposal at the summit, and quickly said he agreed that changes, like increasing the retirement age, are necessary.
"The math is unmistakable," Rubio said.
When Social Security was created under President Franklin D. Roosevelt, there were 16 workers for every eligible retiree, Rubio said. Today, it's three workers to each recipient.
Rubio defends experience, legislative record 08:29
"If we want to reform these programs in a way that doesn't impact anyone like my mother—people currently in the program or about to retire—it will require my generation and your generation to accept that our Social Security and our Medicare is still going to be the best in the world, but it's going to look different than our parents' Social Security and their Medicare," he said.
Bush, meanwhile, weighed in Friday morning at an event in Manchester, backing a higher eligibility age.
"I think we need to raise the retirement age, not for people that are already nearing, receiving Social Security, or already on it, but raise it gradually, over a long period of time for people that are just entering the system. And I think we need to do that in relatively short order," he said.
Other Republicans also could wade into the debate.
The New Hampshire Republican Party is hosting its First-in-the-Nation Leadership Summit at the Crowne Plaza Hotel in Nashua. Christie, Rubio and Bush took the stage on Friday, the first day. Kentucky Sen. Rand Paul spoke Saturday morning, and was scheduled to be followed by Texas Sen. Ted Cruz, Wisconsin Gov. Scott Walker and several other White House aspirants.
Photos: Chris Christie's career in photos
New Jersey Gov. Chris Christie, joined by his family, announces his candidacy for the Republican presidential nomination on June 30 at Livingston High School in Livingston Township, New Jersey.
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Photos: Chris Christie's career in photos
Christie takes questions from Bruce Rastetter at the Iowa Ag Summit on March 7 in Des Moines, Iowa.
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Photos: Chris Christie's career in photos
Christie jokes with host Laura Ingraham as he addresses the annual Conservative Political Action Conference at National Harbor, Maryland, on February 26.
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Photos: Chris Christie's career in photos
Christie campaigns for Wisconsin Gov. Scott Walker during a campaign stop at the GOP field office in Hudson, Wisconsin, on September 29, 2014.
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Photos: Chris Christie's career in photos
Christie enters the Borough Hall in Fort Lee, New Jersey, on January 9, 2014, to apologize to Mayor Mark Sokolich for the George Washington Bridge lane closures -- a scandal that became known in the media as "Bridgegate."
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Photos: Chris Christie's career in photos
Christie speaks at a news conference on January 9, 2014, in Trenton, New Jersey, about his knowledge of an alleged traffic study that stopped traffic at the George Washington Bridge. Christie addressed allegations that his deputy chief of staff signaled for the New York and New Jersey Port Authority to close lanes on the George Washington Bridge to punish the Fort Lee mayor for not endorsing Christie during the election.
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Photos: Chris Christie's career in photos
Christie arrives to speak at his election night event after winning a second term as governor on November 5, 2013, in Asbury Park, New Jersey. Christie defeated his Democratic opponent, Barbara Buono, by a large margin.
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Photos: Chris Christie's career in photos
Christie talks to business owners affected by a massive fire that burned a large portion of the Seaside Park boardwalk, which had recently been rebuilt after Superstorm Sandy, on September 14, 2013, in Seaside Heights, New Jersey.
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Christie speaks to members of the Hudson County Building Trades Council after receiving their support for his re-election campaign for governor on July 1, 2013, in Jersey City, New Jersey.
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Photos: Chris Christie's career in photos
Christie greets President Barack Obama on his arrival in Atlantic City, New Jersey, on October 31, 2012, to visit areas hit by Superstorm Sandy. Christie was later criticized by some in his party for his warm welcome of Obama.
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Christie updates members of the media on damage and recovery efforts related to Superstorm Sandy on October 30, 2012, from the emergency operations center at State Police Headquarters in Ewing, New Jersey.
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Christie and Republican presidential candidate Mitt Romney speak with Romney adviser Bob White on board the Romney campaign bus in Mount Vernon, Ohio, on October 10, 2012.
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Christie takes the stage to deliver the keynote address at the Republican National Convention on August 28, 2012, in Tampa, Florida.
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Christie speaks as he endorses former Massachusetts Gov. Mitt Romney for the Republican presidential nomination on October 11, 2011, in Lebanon, New Hampshire.
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Christie and his family lay white roses on wreckage pulled from Ground Zero during the dedication of the Empty Sky Memorial for 9/11 at Liberty State Park in Jersey City, New Jersey, on September 10, 2011.
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Christie speaks at a Reform Agenda Town Hall meeting at the New Jersey Manufacturers Insurance Company facility on March 29, 2011, in Hammonton, New Jersey.
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Christie, his wife, Mary Pat Christie, and their children attend the third annual New Jersey Hall of Fame Induction Ceremony in Newark, New Jersey, on May 2, 2010.
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Christie waves to supporters with Lt. Gov.-elect Kim Guadagno, left, on November 3, 2009, in Parsippany, New Jersey. Christie defeated incumbent Democrat Jon Corzine.
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Christie and his running mate, Kim Guadagno, left, pose for photographs after making phone calls to voters at Monmouth County Republican Headquarters in Freehold, New Jersey, on November 2, 2009.
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Photos: Chris Christie's career in photos
Before getting into politics, Christie was a New Jersey attorney. Here Christie speaks with the media on May 8, 2007, outside the federal courthouse in Camden, New Jersey, after six men were arrested on charges of planning to attack the Fort Dix military base.
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Christie speaks to the media about an FBI sting with Russian Gen. Sergei Fomenko, right, of the Federal Security Service and FBI Agent Louie Allen on August 13, 2003, in Newark, New Jersey.
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