A national CNBC poll finds President Barack Obama holds a commanding lead over Mitt Romney on the key issue of who would be better for the economy over the next four years.

Obama gets that nod even though Americans, by overwhelming margins, believe the economy is worse now than it was four years ago when Obama's term began.

Our latest CNBC All-America Economic Survey of 800 American adults across the nation shows Obama with a nine-point lead over Romney, 43 percent to 34 percent, on who would do a better job on the economy in the future.

At the same time, 55 percent say the economy is worse off than it was four years ago and just 22 percent think it’s better. Seventeen percent say it’s about the same.

The scientific poll of 802 randomly chosen adults, including 201 who only have a cellphone, was conducted by the Hart/McInturff Group from Sept. 17 through Sept. 20. It has a margin of error of plus or minus 3.5 percent.

In June, CNBC asked Americans who had “good ideas for how to improve the economy,” a variation on the question asked in this poll. Romney held a 39 percent to 33 percent advantage over Obama. Compared with the prior poll, Romney maintained his 80 percent support among Republicans, but lost ground with independents.

Obama gained substantial support among African-Americans, Latinos, and Democrats, and picked up a small percentage among whites.