For weeks, speculation has mounted over what Gov. Mitt Romney (search), who's contemplating a 2008 presidential run, would do with a bill expanding access to emergency contraception.

Romney dispelled that uncertainty on Monday, as he returned to Massachusetts from vacation to veto the legislation just hours after it landed on his desk. The largely symbolic veto unleashed a flood of praise from anti-abortion activists and fury from abortion rights (search) advocates. The bill passed with veto-proof margins in both the House and Senate.

The Republican governor explained his decision by saying that the medication prevents fertilization, but can also halt a fertilized egg from developing — something which supporters of the legislation say is not the same as abortion.

"If it only dealt with contraception, I wouldn't have a problem with it," Romney said.

In an opinion article in Tuesday's Boston Globe, Romney discussed his veto and criticized the landmark Roe v. Wade (search) ruling legalizing abortion, saying the country is divided over the issue and "states should determine their own abortion laws and not have them dictated by judicial mandate."

He had said during his 2002 campaign that he personally opposes abortion, but would be a strong supporter of state and federal laws that guarantee abortion rights.

In his opinion piece, Romney said his view has evolved in office, particularly during the recent debate over stem cell research (search). Legislators passed a law in May over Romney's veto that allows scientists to create cloned embryos and extract the stem cells for medical research.

The emergency contraception issue had taken on unexpected prominence because of the widely held view that Romney is trying to court conservative voters who would be key to a presidential run.

Romney also said during the 2002 gubernatorial campaign that he supported wider access to emergency contraception. But after the bill began making its way through the Legislature, he said he needed to consult with medical experts on its impact.

Signing the bill, Romney said, would violate the campaign pledge he made not to change the state's abortion laws. Romney also cited the lack of restrictions on age, which was debated in the House before lawmakers passed the bill last week.

Sen. Susan Fargo, D-Lincoln, called the governor's "a cowardly smoke screen."

"His real motivation is his political ambitions, not the health and welfare of Massachusetts women," Fargo, the Senate chairwoman of the Committee on Public Health, said in a statement.

Outside the governor's office, a group of young women wore T-shirts and held placards reading, "Mitt Romney — keep your word. Sign the EC bill." As Romney's press conference let out, they chanted "Mitt Romney, we want the pill. Why did you veto the bill?"

National anti-abortion groups said they were pleased with the decision. Connie Mackey, vice president for government affairs at the Family Research Council, calls Romney's act "a positive" that would likely be viewed favorably by anti-abortion voters.

"I think that pro-life politics will be very important in the next election, as they proved to be in the last election," she said.

Carrie Gordon Earll, spokeswoman for Colorado-based Focus on the Family, said her organization also supported the governor's action, but said that there are "a lot of pro-life governors in this country," and Romney's action wouldn't necessarily give him a boost over others.

The bill would require hospital emergency room doctors to offer the medication to rape victims, and would make it available without prescription from pharmacies. A provision that exempted Catholic hospitals was dropped.

The medication, which is different from the abortion pill RU-486 (search), is a hormone in pill form which, when taken after unprotected sex, prevents ovulation, stops the egg from being fertilized by sperm, or stops a fertilized egg from attaching itself to the uterus wall.

It was not immediately clear when a veto override might take place. The Legislature has adjourned for the summer, but lawmakers could be called back to vote on it.

Lt. Gov. Kerry Healey had publicly supported the legislation, urging her fellow Republican to sign the bill. It was widely seen as an effort by Healey to emerge from Romney's shadow as he considers whether to run for re-election in 2006 or focus instead on a 2008 run for the White House.