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Chaos reigned in the final minutes of the Texas Senate late Tuesday night as opponents of a strict abortion bill succeeded in killing the measure, using a sprawling Democrat-led filibuster, egged on by noisy "unruly mob" protests, to blunt last-ditch efforts by Republicans to save the legislation.

The drama centered largely around Democratic state Sen. Wendy Davis, who staged an hours-long, old-fashioned filibuster on the Senate floor against a bill to ban abortions after 20 weeks of pregnancy.

Republicans initially succeeded in cutting her filibuster off, in part by objecting when another lawmaker helped her with a back brace. But protesters picked up where she left off, jeering at lawmakers as they rushed to meet a midnight deadline for the bill.

Republicans initially insisted they made it, but Lt. Gov. David Dewhurst later acknowledged they did not.

Dewhurst denounced the more than 400 protesters who staged what they called "a people's filibuster" from 11:45 p.m. to well past midnight. He denied mishandling the debate.

"I didn't lose control (of the chamber). We had an unruly mob," Dewhurst said. He then hinted that Gov. Rick Perry may immediately call another special session, adding: "It's over. It's been fun. But see you soon."

The chaos capped one of the most unusual stand-offs in any state legislative session this year.

Davis spent most of the day staging her filibuster, attracting wide support, including a mention from President Obama's campaign Twitter account. Her Twitter following went from 1,200 in the morning to more than 20,000 by Tuesday night.

"My back hurts. I don't have a lot of words left," Davis said when it was over and she was showered with cheers by activist who stayed at the Capitol to see her. "It shows the determination and spirit of Texas women."

Davis' mission, however, was cut short.

Rules stipulated she remain standing, not lean on her desk or take any breaks -- even for meals or to use the bathroom. But she also was required to stay on topic, and Republicans pointed out a mistake and later protested again when another lawmaker helped her with a back brace.

Republican Sen. Donna Campbell called the third point of order because of her remarks about a previous law concerning sonograms. Under the rules, lawmakers can vote to end a filibuster after three sustained points of order.

After much back and forth, the GOP voted to end the filibuster minutes before midnight, sparking the raucous response from protesters in the final 15 minutes before the deadline.

Initially, Republicans insisted they had started voting before the midnight deadline and passed the bill that Democrats spent much of Tuesday filibustering. But after official computer records and printouts of the voting record showed the vote took place on Wednesday, and then were changed to read Tuesday, senators convened for a private meeting.

An hour later, Dewhurst was still insisting the 19-10 vote was in time, but said, "with all the ruckus and noise going on, I couldn't sign the bill."

The measures would have closed almost every abortion clinic in Texas, a state 773 miles wide and 790 miles long with 26 million people. A woman living along the Mexico border or in West Texas would have to drive hundreds of miles to obtain an abortion if the law passes.

In her opening remarks, Davis said she was "rising on the floor today to humbly give voice to thousands of Texans" and called Republican efforts to pass the bill a "raw abuse of power."

"Partisanship and ambition are not unusual in a state capitol but here in Texas right now it has risen to a level of profound irresponsibility," Davis was quoted as saying by MyFoxAustin.com.

Democrats chose Davis to lead the effort because of her background as a woman who had her first child as a teenager and went on to graduate from Harvard Law School.

In the hallway outside the Senate chamber, hundreds of women stood in line, waiting for people in the gallery to give up their seats. Women's rights supporters wore orange T-shirts to show their support for Davis, and Dewhurst reminded those in the gallery that interrupting the proceedings could results in 48 hours in jail.

Davis tried to stay comfortable and sharp by shifting her weight from hip to hip and slowly walking around her desk while reading notes from a large binder on her desk.

MyFoxAustin.com reported that a protester in the Senate gallery, identified as Mike Bradford, was removed by security after causing a disturbance.

He explained his opposition to abortion in an interview with reporters outside the gallery.

"I see all the supporters mostly I see, firstly white women, who are supporting abortion but yet abortions are effecting a certain demographic that's not included in the people supporting it,"  Bradford told the station.

Twice in the first six hours, anti-abortion lawmakers questioned Davis about the bill, presenting their arguments that it would protect women or that abortions were wrong. Davis answered their questions but did not give up control of the floor.

"This is really about women's health," said Sen. Bob Deuell, who introduced a requirement that all abortions take place in surgical centers. "Sometimes bad things can happen."

Davis questioned then why vasectomies and colonoscopies aren't also required to take place in such clinics. "Because I've been unable to have a simple question answered to help me understand how this would lead to better care for women, I must question the underlying motive for doing so."

Davis read testimony from women and doctors who would be impacted by the changes, but who were denied the opportunity to speak in a Republican-controlled committee. During one heart-wrenching story describing a woman's difficult pregnancy, Davis choked up several times and wiped tears.

The bill would ban abortion after 20 weeks of pregnancy and force many clinics that perform the procedure to upgrade their facilities and be classified as ambulatory surgical centers. Also, doctors would be required to have admitting privileges at a hospital within 30 miles -- a tall order in rural communities.

Click here for more from MyFoxAustin.com.

The Associated Press contributed to this report