SOON AFTER becoming Massachusetts governor, Willard Mitt Romney retroactively imposed new taxes on non-residents, including Granite State citizens who work, conduct business, and/or invest in the Bay State. Romney's higher taxes reached into New Hampshire and helped vacuum at least $95 million in marginal income back across the border.

According to Massachusetts Department of Revenue figures, the total amount that New Hampshire taxpayers surrendered to Massachusetts grew from $213.6 million in 2002 to $248.9 million in 2006, a 16.5 percent increase. (Data for 2006 are preliminary.)

Had 2002's tax baseline remained flat, New Hampshire taxpayers would have kept $95 million in cumulative payments to Massachusetts since 2003. Higher revenues often are a supply-side effect of tax cuts. This is not so when taxes increase.

Massachusetts tax revenues from New Hampshire residents increased even as the number of New Hampshire residents who paid Massachusetts taxes fell 2.3 percent -- from 89,304 in 2002 to 87,320 in 2006. The checks shrank in number, but swelled in value. The average tax payment from New Hampshire expanded $458 -- from $2,392 in 2002 to $2,850 in 2006 -- up 19.2 percent.

"That's even more remarkable when you consider that the number of New Hampshire taxpayers who pay (as opposed to simply file) didn't change in what appears to be any statistically significant way during this period, yet the average tax payment went up substantially," says Cato Institute scholar Stephen Slivinski.

These higher payments perfectly coincide with legislation Romney signed on March 5, 2003, retroactive to that Jan. 1. Under Romney's law, "gross income derived from. . . any trade or business, including any employment," would be taxable, "regardless of the taxpayer's residence or domicile in the year it is received."

These rules now cover "gain from the sale of a business or of an interest in a business, distributive share income, separation, sick or vacation pay, deferred compensation and [state-taxable] nonqualified pension income." On Aug. 9, 2004 Romney also taxed non-residents' shares of income from real-estate partnerships.

"Romney created these taxes new," says Robert Roughsedge, a Hampton attorney who works in Boston. "He taxed more people and companies than before. This is what a dying state must do to keep the tax base. This is not a pro-growth, Reagan-type answer to the problem. . . . Romney chose to tax the people who left, increase the people outside of the state subject to taxation, and probably remove the incentive to leave by increasing the cost."

"This research confirms what I said when Mitt Romney started attacking Rudy Giuliani on the commuter-tax issue in New York," says former Republican Massachusetts Gov. Paul Cellucci, who supports Giuliani.

"That was an existing tax. Mayor Giuliani had other priorities in terms of tax cutting. He provided broad-based tax relief for New York residents and businesses, something Mitt Romney could not do in Massachusetts. It's ironic that Mayor Giuliani did not raise taxes on commuters, yet he gets criticized by a guy who did raise taxes on commuters, in particular people in New Hampshire who work in Massachusetts."

Had Romney's spokesmen commented, as requested, they might have observed that he sped a $275 million capital gains tax rebate, scored property-tax relief for seniors and secured a two-day, tax-free shopping holiday.

Nonetheless, Merrimack's Bob Bevill, chairman of the conservative New Hampshire Eagle Forum, is among those who condemn Romney for $283 million in business "loophole closures" and $501.5 million in increased fees on marriage licenses, gun registrations, gasoline deliveries, property-deed certificates, and more.

"New Hampshire taxpayers should be concerned that Mr. Romney will continue his semantically challenged shell-game of raising taxes, through increased users fees and special tariffs, while publicly stating that he has not raised taxes," Bevill says. "A vote for Romney is a vote for higher taxes -- no matter what they are called."

New York commentator Deroy Murdock is a media fellow with the Hoover Institution on War, Revolution and Peace at Stanford University.