Rasmussen also found a Republican edge on many other issues. Democrats led Republicans 41 percent to 38 percent on education -- but the GOP led 49 percent to 40 percent on national security, 40 percent to 34 percent on immigration, 46 percent to 39 percent on abortion, 34 percent to 33 percent on ethics and corruption, and -- get this -- 42 percent to 37 percent on Social Security.

When Republicans are winning on Social Security, it's bad news for the Democrats.

Most ominous for Obama is the GOP lead on the economy, taxes and immigration, and the party's parity on health-care reform. The issues that will dominate the next few months are all working for the Republicans.

It's amazing how quickly Obama has lost his lead. His ratings had fallen steeply after his inauguration. Most polls had his job-approval dropping 13 points in his first three months. But then his numbers revived with the adulatory coverage at his first-100-days mark. Buoyed by hopes of a swift recovery, voters and the stock market gave him a break, and his ratings and the Dow rose sharply.

But since April, he has been dropping fast -- and his alarming losses on his central agenda issues portend further declines.

Congressional elections are still more than a year off, but Obama needs strong approval ratings to steer his legislative package through Congress. If he's sagging in the low 40s or high 30s by the fall, he probably won't be able to persuade moderate Democratic senators to walk the plank and vote for cap-and-trade, health-care reform, higher taxes or an immigration amnesty.

His chief legislative achievements, in other words, may already be behind him.