WASHINGTON (AP) — A freshman GOP senator is jumping into the debate on how to avoid a "fiscal cliff" of tax hikes and automatic spending cuts, advocating a mix of tax increases with curbs on Social Security and Medicare benefits.

Tennessee Sen. Bob Corker is circulating a 10-year, $4.5 trillion plan loaded with controversial proposals, including a less generous inflation adjustment for Social Security, and a gradual increase in the regular Social Security retirement age to 68 and the Medicare eligibility age to 67.

Corker's plan also includes $749 billion in higher tax revenue claimed by capping itemized deductions at $50,000, a proposal that hits wealthier taxpayers the hardest.