The president took his pro-reform message to Maine, a politically friendly state he carried by nearly 20 points in the 2008 general election. While in New England, he also planned to make a quick stop in Massachusetts for a couple of Democratic National Committee fundraisers.

Democrats are celebrating the enactment of the landmark US$940 billion measure, but the country as a whole remains sharply divided over its merits. Conservatives insist it will do little to slow spiraling costs and say businesses will be burdened by a slew of new regulations and taxes.

The president sought to rebut that argument on April 1, in part by highlighting a tax credit designed to help small businesses provide coverage for their employees.

Under the new health care law, small businesses are immediately eligible for a tax credit covering 35 percent of the premiums paid to help cover their workers. The credit is set to expand to 50 percent of premium costs in 2014. Firms can claim the credit between 2010 and 2013, and for any two years afterward.

In order to qualify for the credit, a company needs to have fewer than the equivalent of 25 full-time workers, according to the administration. It must also pay average annual wages under US$50,000 and cover at least 50 percent of its workers' health care coverage.

The White House Council of Economic Advisers has said that roughly 4 million small businesses are eligible for the credit if they provide health insurance. The Internal Revenue Service plans to send postcards to millions of small businesses potentially eligible for the credit, urging them to take advantage of it.