RALEIGH Standing in a darkened hallway at 1:30 a.m., moments after House Republicans overrode a veto of legislation that weakened a political enemy, Speaker Thom Tillis defended a surprise midnight session as efficient and transparent.

"There may be some people who don't like the fact we are here tonight, but the fact of the matter is we got it done," the Mecklenburg Republican said.

Democrats gathered minutes later to criticize the GOP maneuvering as a legislative coup, drawing to a close a dizzying 12-hour political drama that was the most divisive since Republicans took power last year.

"The Republicans in the General Assembly didn't have the votes to get what they wanted legally," Gov. Bev Perdue said in a written statement. "So, in the dark of night, they engaged in an unprecedented, unconstitutional power grab."

The move appeared to betray Republican promises for sunshine on government, political observers said.

"Not only have things not changed, but they may be at a worse place than we've ever seen before," said Bob Phillips, executive director of Common Cause of North Carolina, a group that advocates for government transparency.

Republican leaders dismiss such concerns. When Tillis and company took control of the state legislature for the first time in more than a century they promised openness. A day after the 2010 election, House GOP leader Paul "Skip" Stam of Apex said: "We pledge to bring much needed transparency to the legislative branch of state government."

But Democrats complained often last year that the budget was clouded in secrecy and Republicans held questionable closed-door meetings with lobbyists on major issues.

In the early morning interview, Tillis said his previous statements declared veto overrides are fair game at any time, putting the public on notice. "This should be a learning experience," he said.

Asked if the process was fair to interested members of the public, Tillis said: "They are welcome. They are probably not here. But anybody should know" to pay attention.

In the daylight Thursday, House Republicans continued to rebuff criticism. "It seemed to make sense to stay on a couple more hours," said state Rep. Nelson Dollar, a top Republican from Cary. "Sessions that clock in at 12:01 a.m. at night are not unusual in the General Assembly at all," he added referring to the previous Democratic leadership.

The veto override removing an automatic payroll deduction for dues that teachers pay to the N.C. Association of Educators came as a surprise end to a special session about the state's Racial Justice Act. Perdue called the legislature into session, as required by the state constitution, to consider her veto of a bill that basically repealed the act. To consider other matters, the House added a special session for 12:45 a.m. GOP leaders didn't reveal the potential legislation for consideration until 12:15 a.m. and most lawmakers didn't know the votes to come.

Democrats were infuriated. "I can't tell you my real reaction," said nine-term Rep. Beverly Earle of Charlotte. "Some of these things I have never ever seen before. I think the House has reached a new low."

The Senate nullified the governor's veto on the teachers' dues bill in July but the matter sat on the House calendar because Republicans there didn't have the votes to override. The vote tally changed when three Democratic lawmakers missed the early morning vote for health reasons. Two of those lawmakers - Reps. William Wainwright and Dewey Hill - left Wednesday evening before the vote and Democratic Rep. Larry Womble is still hospitalized in critical condition after a car crash.

Two Republicans excused from the Wednesday session were called to Raleigh for the early morning vote. Two Democrats also broke party ranks and gave Republicans the three-fifths majority needed for passage.

Democrats argue that adding a new session to consider other legislation was unconstitutional. The teachers union expects to file a legal challenge in court.

Republicans say the state constitution prohibits consideration of other bills outside the call of the special session but not joint resolutions, such as the one that let them reconvene. Constitutional experts contend the issue rests on untested legal grounds, given that the governor didn't receive constitutional veto power until the mid-1990s, and now similar cases have been filed. "The state constitution itself does not answer the question clearly," said Michael Crowell, an expert at the UNC-Chapel Hill School of Government.

Other lawyers such as Jeanette Doran, the executive director of the N.C. Institute for Constitutional Law, see it more clearly defined. She said the constitution supported Republicans' actions. "Maybe it was a little sneaky, but a little sneaky isn't the same as unconstitutional," said Doran, who said she takes a conservative view of constitutional language.

Staff researcher Brooke Cain and Charlotte Observer staff writer Jim Morrill contributed.