(MONEY Magazine) – Watch out: To keep the Social Security retirement trust fund from running in the red, House Ways and Means Committee chairman Dan Rostenkowski has just lobbed the biggest grenade yet in the battle over the size of future Social Security benefits and employment taxes. And the target is you. Rosty's bill would 1) raise the Social Security tax rate from the current 6.2% to 8.15% over a 38-year period, beginning in 2020; 2) raise the age to get full Social Security benefits from 65 to 67 in 2016, instead of 2027 as now scheduled; and 3) gradually slice benefit checks beginning in 2003. An average earner (making $24,090 a year today and eligible for Social Security of $829 a month) would lose 8.4% over 50 years. A high earner ($60,600 with a $1,147 benefit) would lose 20.2%. Since the Social Security retirement and disability trust fund isn't expected to run out of money until 2029, Congress isn't likely to approve Rosty's bill, or some variant of it, until next year at the very earliest. However, a measure to make the Social Security Administration an independent agency, with more power and visibility, will probably pass in '94. So as you save for retirement, keep in mind that eventually middle- and upper-middle-income Social Security beneficiaries will almost certainly pay more taxes in return for less in benefits. Says Eugene Steuerle, co-author of Retooling Social Security for the 21st Century: "The current system is overpromised and must be reformed. We all have to get ready for that day."