I love my commonwealth. The economy is robust. Taxes are low (5% sales tax, 5.35% flat income tax, 12% capital gains tax). Anyone who wishes can marry without running into out-of-date legal impediments. And now we have universal health coverage.

BOSTON, April 12 — In a ceremony full of pomp and political backpatting, Gov. Mitt Romney signed Massachusetts’ landmark health care legislation Wednesday, setting the stage for the state to be the first to provide health coverage to virtually all of its citizens.

But the celebratory atmosphere was accompanied by some friction because Mr. Romney, a Republican, vetoed a provision some Democrats and health care advocates adamantly support: a requirement that employers who do not provide health insurance to their employees pay the state up to $295 per worker each year.

Leaders of the overwhelmingly Democratic legislature, which passed the bill last week, said they expected to override that veto in the next few weeks and were examining Mr. Romney’s vetoes of seven other less controversial provisions. . . .

The law is projected to provide coverage for about 515,000 of the state’s 550,000 uninsured people and leave less than 1 percent of the population uncovered. It goes further than those of any other state.

It requires residents to obtain health insurance by July 1, 2007. People who can afford insurance and do not buy it will be penalized on their state income taxes.

The law takes the $1 billion in the state’s free-care pool, which paid for medical care for patients without insurance, and uses it to subsidize insurance for people who cannot afford it. The legislation also makes it possible for more individuals and businesses to buy insurance with pre-tax dollars, saving them money. And it includes a system to encourage insurance companies to provide more affordable plans with fewer benefits or higher deductibles.