After early success, Virginia conservatives have seen some of their highest priorities thwarted in the General Assembly.

Several marquee bills related to home-schooling and welfare, abortion and illegal immigration were killed or gutted in the past two weeks at the hands of four moderate Senate Republicans, including Majority Leader Thomas K. Norment Jr. (James City). Gov. Robert F. McDonnell (R) himself played a role.

The stunning defeats came in a year when Republicans took full control of Richmond, buoying conservatives whose agenda had died in a Democratic-led Senate. They pushed an ambitious legislative plan but ran into unexpected opposition from moderate members of their own party.

That has frustrated and even angered some conservative lawmakers and activists, the core of the Virginia Republican Party.

“The base out there is looking at this, and they were told for years that it’s the Democrats holding things up,” said Del. Robert G. Marshall (R-Prince William). “We hold an election, we take charge and guess what? It’s the Republicans holding things up. This is not good news for the conservatives around Virginia at all.”

Four longtime moderate Republicans — Norment and Sens. Harry B. Blevins of Chesapeake, Frank W. Wagner of Virginia Beach and John C. Watkins of Powhatan — were behind many of the defeats.

At the start of the session, McDonnell, a potential vice presidential pick who has cultivated an image of genial aisle-crosser, had urged members of his party not to overreach. “That’s the Virginia way,” he told them.

More than Southern civility was at stake. If conservatives pushed too hard too quickly, they could turn off swing voters in this year’s presidential and U.S. Senate races, political observers have said. Nor would it do much for McDonnell’s national political ambitions, because signing a host of divisive bills might make him a liability with moderate voters.

But with Republicans controlling every lever of power for the second time since the Civil War, some conservatives saw no reason to wait. The Virginia Conservative Caucus rolled out an 80-bill agenda, twice the number of bills it sponsored last year.

They had some wins, even though some of the hot-button bills had not been the priorities of the governor or House and Senate leaders. They overturned a 19-year-old law limiting handgun purchases to one per month; passed a bill allowing faith-based adoption agencies to turn away, for religious reasons, gay applicants; and approved a $10 million-a-year tax credit for a private school vouchers for poor and middle-class students.

And then the conservative revolution seemed to hit a wall, as if Republicans belatedly decided to heed the governor’s call.

Moderate Republicans helped kill measures that would have allowed home-schooled children to play public school sports; subjected welfare recipients to drug testing; defined a fertilized egg as a person; denied state-funded abortions to poor women with grossly deformed fetuses; and freed schoolgirls from a mandate to get immunized against a sexually transmitted virus linked to cervical cancer.

Republicans greatly softened a bill requiring ultrasounds before abortions. They gutted a measure meant to crack down on illegal immigrants.

In some cases, the legislation had cleared major hurdles and seemed destined for the governor’s desk when it zigged and zagged. Antiabortion measures in particular have lurched forward and back.

The tide seemed to turn about the midway point in the session, as comedians and commentators on national television fanned an uproar over a bill requiring that women have an ultrasound involving a vaginal probe before getting an abortion.

On Feb. 22, at McDonnell’s urging, the bill was watered down. The next day, the personhood bill cleared a Senate committee. But in a highly unusual move later that day, the Senate voted to send it back to the committee, effectively killing it. Two antiabortion Democrats abstained, and Norment, Watkins, Wagner and Blevins voted with the Democrats. Norment seconded the motion to send it back.

Over the next eight days, a string of other conservative bills died unexpectedly, mostly in the Senate and it committees. Among them was the legislation that would have repealed a mandate that sixth-grade girls be immunized against the virus linked to cervical cancer.

It’s normal for bills to go by the wayside, McDonnell said this week. “You know, Democrats try to tax about everything that moved this year. Those were rejected. They tried to put marijuana in [liquor] stores. That was rejected. House members, Republicans, put in other bills. Some of those were rejected.”

But some conservative activists see the defeats as nothing short of a betrayal. Some said they saw this coming, having vowed at the start of the session to keep an eye on suspected moderates. But others’ expectations for the session have been dashed.

“You had a lot of people that had their hopes up,” said Mark Kevin Lloyd, chairman of the Virginia Federation of Tea Party Patriots. “They thought by putting more conservatives in office, it would give the rest of them a spine. It hasn’t happened yet — to the satisfaction of many.”

Del. Ben L. Cline (R-Rockbridge), co-chairman of the conservative caucus, said the setbacks were balanced by progress on taxes, Second Amendment rights and education reform.

“Like any session, you get some victories and some defeats,” he said. “You work hard to make sure those defeats are turned into victories next time around.”

Norment said that some conservative senators have asked about his votes, but not in “an ugly way.” Some special-interest groups have approached him as well, he said.

“There are pieces of legislation that become a matter of conscience with you that you can’t embrace,” Norment said. “You hope that your colleagues understand that.”

Blevins, a retired school principal and coach who voted against the home-school sports bill and was the swing vote on abortion measures, said he listens to both sides on a bill rather than simply following his party’s position.

“I don’t see how we get anything done up here unless we have some people who are willing to say, ‘You know, I didn’t think I’d like that. Now that I’ve heard more about it, I’m inclined to think maybe that’s not a bad thing after all,’ ” he said. “I’ve thought a lot about being called a moderate. I’ve probably been called things a lot worse than that.”