President Obama's courtship of Republicans hit a critical point last week when he unveiled a budget proposal pitched as an effort at compromise. But a new Washington Post-ABC News poll finds Americans' initial reactions to the framework tilting negative, with broad opposition from Republicans and little public support for a key idea to reduce increases in  Social Security payments.

Overall, roughly one-third of Americans offer no opinion on Obama's budget, but those who do, lean against it (30 percent approve; 38 percent disapprove). The negativity stems from large opposition among Republicans (63 percent) and a negative split among independents (26 percent approve; 41 percent disapprove).

Democrats are more positive about the budget plan, but far from unanimous: 52 percent approve, far lower than Obama's 83 percent overall job approval rating among fellow partisans.

The poll finds 51 percent of Americans oppose changing the way Social Security benefits are calculated to increase at a slower rate in a move known as the chained consumer price index, or "chained CPI" (Read the excellent Fix explainer on how it works). The idea is a Republican demand that Obama included in his budget for the first time despite opposition from Democratic leaders.

While both Republicans and Democrats tilt against the idea, chained CPI faces the steepest opposition from older Americans. More than six in 10 of those ages 65 and older oppose a slower benefit increase for Social Security, as do 57 percent of those approaching retirement age (ages 50 to 64).

Income is also a dividing line in tolerance for Social Security cuts. Americans with annual incomes of at least $100,000 back the proposal by a 53 to 39 percent margin, but support plummets to 38 percent among those making $50,000 to under $100,000 and to 33 percent among those with incomes below $50,000. Support bottoms out at 25 percent among those with lower incomes who are over the age of 50.

Clement is a pollster with Capital Insight, the independent polling group of Washington Post Media.