Updated at 10:30 a.m. Thursday with details on absenteeism and comment from O'Rourke.

WASHINGTON — For anyone doubting the flurry of polls showing a neck-and-neck Senate race in Texas, there's fresh proof this week that Rep. Beto O'Rourke has the full attention of Sen. Ted Cruz and other Republicans.

On Monday, Cruz stepped up attacks on the El Paso Democrat by asserting that O'Rourke's defense of NFL football players who kneel during the national anthem is no better than support for flag burning.

He's added campaign events at the last minute, keeping him in Texas through Friday night — even though that meant skipping days of votes in the Senate, where before the summer he'd prodded leaders to cancel the traditional August recess. Which they did.

"We must not waste one minute of one day while we work to fulfill the promises we made to the American people," Cruz said in early June. "By working through August, we will continue to fight for more policy achievements and to deliver for the American people who elected us."

Late Tuesday, the state GOP tweeted out an arrest photo of O'Rourke from two decades ago, ramping up efforts to reshape the challenger's image from fresh faced "Kennedy-esque" optimist to dangerous radical.

"There's always the chance that Robert `Beto' O'Rourke won't debate Senator Cruz because he got into a hazy situation," the tweet reads. Over the mug shot, the GOP superimposed the words "Sorry. Can't Debate. Had a little too much to drink."

The state party also dusted off a photo of the future congressman from his days as a punk rocker. He's on the left with a goatee, long hair and a flowery dress.

Maybe Beto can’t debate Ted Cruz because he already had plans... pic.twitter.com/LdqKTh3yK4 — Texas GOP (@TexasGOP) August 28, 2018

The quickening pace of attacks comes in the aftermath of polls showing O'Rourke tied with Cruz, or close to it, and with major Cruz allies expressing increasing concern about his ability to hang on to the seat. The Club for Growth, an anti-tax group, plans a "seven-figure ad blitz" on his behalf.

O'Rourke's campaign didn't respond to a request for comment about the mug shot attack.

Cruz aides declined to speak on the record about the senator skipping votes.

In May, Cruz co-signed a letter with a dozen other GOP senators urging Majority Leader Mitch McConnell to consider keeping the Senate in session "nights and weekends" and to cancel the August recess.

Two weeks ago, a frustrated McConnell privately lectured GOP senators about absenteeism.

On Tuesday, Cruz missed a half-dozen roll calls to confirm a federal judge, a governor for the Federal Reserve and other posts. None was controversial or close. He missed votes last week, too, including one on a topic close to his heart, to defund Planned Parenthood.

Sen. John Cornyn of Texas, the majority whip in the Senate, defended Cruz for skipping work in Washington.

"We've gotten a lot done that we would not have gotten done" if the Senate hadn't been in session during August, Cornyn said. He noted that the GOP and Democratic leaders had cut a deal to get about 15 noncontroversial judges and other nominees confirmed this week.

"We really haven't had any close votes that have turned on an individual senator's presence or absence," Cornyn said. "I trust Sen. Cruz to make decisions in the best interest of his campaign and his service. I don't think the fact he may not have been here for a vote or two has affected the outcome of those matters at all."

O'Rourke, 45, was arrested twice in El Paso during his 20s: in 1995 on a charge of attempted burglary and in 1998 for driving while intoxicated.

He has said the first arrest happened after he tripped an alarm while jumping a fence at the University of Texas at El Paso. Prosecutors declined to pursue that case. He received deferred adjudication on the drunken-driving arrest and was not convicted.

"There is no excuse and there's nothing I can say, other than that was very stupid of me and I showed really poor judgment, bad judgment," he told The Dallas Morning News earlier this year. "It was something that I did, and I hope in those 20 years I have been able to contribute to this community. But there is just no excusing for that."

The Republicans aren't the first to use the arrests against him. Winning a congressional seat in 2012 meant overcoming a longtime Democratic incumbent in the primary. Silvestre Reyes, a former sector chief for the Border Patrol, featured his challenger's arrests in ads and on the stump, warning that — along with O'Rourke's desire to legalize marijuana — he couldn't be trusted.

There's always the chance that Robert “Beto” O’Rourke won’t debate Senator Cruz because he got into a hazy situation... pic.twitter.com/4nmd42AEkl — Texas GOP (@TexasGOP) August 29, 2018

The Texas GOP used the same mug shot Reyes used in a 2012 ad. The "hazy situation" verbiage seemed to allude to his attitude toward legalizing pot, though drug charges were not part of either arrest.

The assertion that O'Rourke is dodging a debate with Cruz is arguable.

O'Rourke proposed a half-dozen debates several months ago. After rejecting his entreaties to negotiate a schedule, the Cruz side then pre-emptively proposed five debates on specific dates and topics, insisting the terms were nonnegotiable. O'Rourke refused to accept the terms, and if Cruz has budged, his aides haven't acknowledged that.

The first debate Cruz proposed would have been Friday, in Dallas, with the candidates standing at lecterns discussing jobs, taxes, regulations and the economy.

As for absenteeism, records from GovTrack show that Cruz has missed 14 percent of all roll call votes since joining the Senate -- far worse than the median 1.5 percent lifetime average for current senators -- with huge spikes during his run for president, and a marked rise in recent months.

"He missed nearly a quarter of his Senate votes in 2015, half of his Senate votes in 2016, and has a substantially worse attendance record than most of his colleagues," said O'Rourke spokesman Chris Evans.

O'Rourke, who like Cruz won his seat in 2012, has missed 2.9 percent of votes during his tenure, just slightly above the House average.

The Texas GOP's jab at O'Rourke provoked tart comebacks on Twitter. One user dug up mug shots of prominent Texas Republicans who had faced criminal charges of varying severity, including Ken Paxton, Rick Perry, Tom DeLay and Steve Stockman.

Paxton, the state's attorney general, has been under indictment for more than three years on securities fraud charges.

DeLay was the U.S. House majority leader when he was indicted in 2005 on charges of illegally funneling corporate money to state legislative candidates. Convicted and sentenced to three years in prison, he later won a reversal of his conviction.

Perry, the energy secretary, fended off charges that he abused his authority as governor by threatening to cut funding to the same district attorney who prosecuted DeLay, to force her to resign after being arrested for drunken driving.

Stockman, a disgraced Houston-area congressman, was convicted in April of a massive fraud scheme.

The state GOP attributed the pushback to "out of state liberals, and people who use the word `rad.' ''

Based on the reaction to our tweets we can confirm that Beto is in fact going to receive 100% of the vote from Buzzfeed contributors, out of state liberals, and people who use the word "rad." We feel very owned :'( — Texas GOP (@TexasGOP) August 29, 2018

Cornyn, former head of the party's Senate campaign arm, said Republicans aren't overly worried about Cruz.

"There's no doubt that Beto O'Rourke has raised a ton of money," he said. "It's an impressive amount of money, and certainly, who would have expected a challenger to outraise the incumbent senator, Sen. Cruz?"

But he said Cruz will have enough money to be competitive, and "at this point Beto O'Rourke is a largely unknown quantity other than the image that he's been able to portray. I congratulate him. He's been able to portray an image of somebody who's sort of a fresh new face in American politics and given some hope to the Democratic Party in Texas."

Cornyn, echoing a Cruz line of attack, said that the challenger's views are "out of step" with those of most Texans, and that voters will reject him "once those positions and differences are exposed."

An Emerson College poll released Monday showed Cruz ahead by just 1 percentage point. While the methodology may be flawed, the Cruz campaign quickly incorporated it into a fundraising appeal designed to help him close the gap.

The campaign has jumped on other polls showing anything from a statistical dead heat to a 6-point lead for Cruz.

"Obviously the race appears to be tightening," Cornyn said. "I think when you look at the likely voter turnout models that Sen. Cruz will win by a significant margin."

.@JohnCornyn predicts that @realDonaldTrump will stump for @TedCruz in #Texas: “I would expect that to happen and I hope it does happen. I think they’re considering it but they haven’t picked a date or a location yet,” he tells TX reporters. https://t.co/4OT7DwR04q — Todd J. Gillman (@toddgillman) August 29, 2018

O'Rourke has been collecting donations at a torrid rate, outraising the incumbent by more than $10 million from March to June and pulling almost even in 15 months with Cruz's six-year haul.

He's also surpassed Cruz at retail politicking, by far. But Cruz has extended his time on the stump day by day. On Wednesday, he added stops Thursday and Friday in West Texas, GOP turf that O'Rourke has been working hard.

Cruz has said he would welcome help from President Donald Trump, and Cornyn predicted the president will stump in Texas for his colleague.

"I would expect that to happen and I hope it does happen," he said on a call with Texas news outlets. "I think they're considering it, but they haven't picked a date or a location yet."