Rep. Paul Ryan burst on to the national stage in 2008 with a white paper entitled "A Road Map for America's Future." In the space of four years, he has ridden it to the Republican nomination for vice president.
Ryan's plan, revised annually as the Republican Party's budget proposal, represents the most sweeping effort ever to reduce the explosive growth in Medicare and Medicaid, the twin pillars of the Great Society that provide health care to nearly one in three Americans.
Medicare, the government-run health insurance program for seniors that adds a person to its rolls every eight seconds, would be run largely by private insurers and would cost beneficiaries more or offer them less. Traditional Medicare would remain as an option. The plan would start in 2023, effectively exempting those 55 and over.
Medicaid, the federal-state program covering more than 50 million low-income Americans, would be turned over to the states and cut by $750 billion over 10 years, forcing fewer benefits or higher co-payments.
President Obama's health insurance expansion, passed in 2010 and upheld by the Supreme Court in June, would be repealed. Other low-income programs, such as food stamps, also would be turned into block grants to the states, with limits on growth.
"People are ready for an adult conversation. They're ready for the truth. They're ready for solutions no matter whether they agree on every detail or not," Ryan told USA TODAY in an interview in 2010. "This is no longer the third rail it was once thought to be."
The proposed changes represent an enormous political gamble for Republicans because they would strike at the heart of popular insurance programs long viewed as backbones of stability for millions of families. Seniors and people with disabilities would have to pay more for the best coverage.
Ryan and fellow Republicans avoided including a detailed plan for cutting Social Security benefits or raising the retirement age from 67, where it is headed now, choosing instead to create budget rules that would force both parties to fix Social Security eventually.
"We thought that if we put one out there, it would just be too tempting for the Democrats to attack," Ryan told an audience at the conservative American Enterprise Institute last year.
Under the plan, starting in 2023, new Medicare beneficiaries could choose a private health plan, and the U.S. government would subsidize the cost. Low-income recipients and those with greater health risks would get extra help. The approach is modeled after Medicare's prescription drug program, passed in 2003.
Those 54 and younger would be able to choose from a list of competing private plans. Medicare would provide a payment to subsidize the cost. From then on, the beneficiary would be on his or her own: stay cheap and conserve out-of-pocket costs, or go gold-plate and contribute handsomely.
This year, Ryan toned down his plan a bit by including traditional Medicare as an option. That is patterned after a bipartisan plan he is sponsoring with Democratic Sen. Ron Wyden of Oregon.
While Democrats, including President Obama, have railed against the plan, Ryan reasons that Medicare's exponential growth requires revolutionary solutions.
The Centers for Medicare and Medicaid Services, the federal agency that administers the nation's health care plan for seniors, projects that Medicare will serve 80 million people by 2030, when the last of the Baby Boomers turn 65. Spending on the program is projected to rise by 5.8% annually, topping $900 billion in 2020.
"Our goal here is to leave our children and our grandchildren with a debt-free nation," Ryan said last year. "At stake is America."
The plan for Medicaid has received less attention but is no less sweeping in its scope. Ryan would send the program back to the states in much the same way welfare was transformed in 1996, cutting $750 billion over 10 years.
Ron Pollack, executive director of the health care consumers group Families USA, has warned that the block grants to states would amount to a 33% cut by 2021.
The Center for Medicare Advocacy has called the GOP health care rationing. The Center for American Progress has warned that 16 million seniors and people with disabilities would face higher costs or risk losing Medicaid coverage.
Ryan's selection also sets up a stark debate over tax policy. While Obama has called for raising taxes on people with incomes above $200,000, Ryan's plan calls for reducing the top individual and corporate tax rates to 25% from their current 35% levels. The only other tax rate would be 10%.
He would pay for that by wiping out special-interest tax breaks, many of which benefit the middle class - something Romney has vowed to do as well. Neither man has specified what tax breaks he would eliminate.
Ryan has won respect from most of the nation's leading "deficit hawks" - fiscal experts who long have warned about the need to slash the nation's debt, now $15.9 trillion.
"He is a leader who has the courage to make transformational change proposals," said former U.S. comptroller general David Walker, founder of the Comeback American Initiative, which is leading a nationwide effort to promote deficit and debt reduction.
Ryan's road map, Walker said, "recognizes that spending is the primary problem and that we have to gain control over health care costs." But he faulted it for leaving Social Security and defense spending "off the table."
Maya MacGuineas, president of the Committee for a Responsible Federal Budget, has said Ryan's 2012 budget plan "puts our nation on a fiscally sustainable path, and he deserves praise for making many of the hard choices necessary to do so."
Ryan's plan would cut $6 trillion in spending over 10 years. Obama has proposed a less sweeping $4 trillion reduction over 12 years.
Beyond the numbers, Obama has used Ryan's budget plan to hammer Republicans. In his first public address after announcing his re-election bid in April 2011, Obama delivered a scathing attack on the Ryan plan - with Ryan, invited by the White House, seated in the front row.
"I will preserve these health care programs as a promise we make to each other in this society," Obama said. "I will not allow Medicare to become a voucher program that leaves seniors at the mercy of the insurance industry, with a shrinking benefit to pay for rising costs."
Ryan, who stalked out of that George Washington University speech seething, called Obama's presentation "excessively partisan, dramatically inaccurate and hopelessly inadequate." He's betting voters are ready for tough talk on the deficit.
"At least in 2012," he said last year, "they'll have a real choice."