Enlarge By Charles Dharapak, AP President Obama reaches for a pen to sign the health care bill Tuesday. A poll finds increased support for the measure. USA TODAY/ GALLUP POLL USA TODAY/ GALLUP POLL The new health care bill: Source: USA TODAY/Gallup Poll of 1,005 adults Monday. Margin of error: +/-4 percentage points. WASHINGTON  More Americans now favor than oppose the health care overhaul that President Obama signed into law Tuesday, a USA TODAY/Gallup Poll finds — a notable turnaround from surveys before the vote that showed a plurality against the legislation. By 49%-40%, those polled say it was "a good thing" rather than a bad one that Congress passed the bill. Half describe their reaction in positive terms — as "enthusiastic" or "pleased" — while about four in 10 describe it in negative ways, as "disappointed" or "angry." The largest single group, 48%, calls the legislation "a good first step" that needs to be followed by more action. And 4% say the bill itself makes the most important changes needed in the nation's health care system. "After a century of striving, after a year of debate, after a historic vote, health care reform is no longer an unmet promise," Obama declared in a celebration at the Interior Department auditorium with members of Congress, leaders of advocacy groups and citizens whose personal stories were cited during the debate. "It is the law of the land." LAWSUITS: 13 AGs sue over health bill HEALTH BILL: How six groups will be affected BUSINESS: Employers unclear on impact To be sure, the nation remains divided about the massive legislation that narrowly passed the House late Sunday. Minutes after Obama signed the bill in the East Room, attorneys general from 13 states — led by Bill McCollum of Florida — sued to block the law as unconstitutional. Virginia filed separately. Nearly one-third of those surveyed, 31%, say the bill makes "the wrong types of changes," and 8% say the health care system doesn't need reform. The poll of 1,005 adults Monday has a margin of error of +/—4 percentage points. The findings show receptive terrain as the White House launches efforts to sell the plan, including a trip by Obama to Iowa on Thursday. "The political tides shifted with passage of the bill," White House communications director Dan Pfeiffer says. "It's easy to demonize something large and complex in theory; harder when it becomes law." No one gets overwhelmingly positive ratings on the issue, but Obama fares the best: 46% say his work has been excellent or good; 31% call it poor. For congressional Democrats, 32% call their efforts on health care excellent or good; 33% poor. Congressional Republicans, all of whom voted against the bill, are viewed more negatively. Although 26% of those surveyed rate the GOP's effort as excellent or good, 34% say it has been poor. Republicans vow to stall a final package of fixes to the bill now being debated in the Senate. In the new USA TODAY survey and one taken a month ago, the biggest shift toward support of the bill was among low-income Americans, minorities and those under 40. That has created a yawning age divide: A solid majority of seniors oppose the bill; a solid majority of those younger than 40 favor it. Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. Read more