(Reuters) - It was no more Mr. Nice Guy for Beto O’Rourke.

U.S. Rep. Beto O'Rourke poses for pictures after a debate with U.S. Senator Ted Cruz (not shown) at the KENS-5 Studios in San Antonio, Texas, U.S., October 16, 2018. Tom Reel/San Antonio Express-News/Pool via REUTERS

Falling behind in the polls and running out of time, the Democratic contender for the U.S. Senate went on the attack against Republican incumbent Ted Cruz in a raucous debate in Texas on Tuesday night, calling him dishonest and resurrecting President Donald Trump’s campaign nickname, “Lyin’ Ted.”

Cruz fired back repeatedly, casting O’Rourke as out of touch with the values of Texas voters during a free-swinging debate that turned personal over divisive issues such as healthcare, climate change and the possible impeachment of Trump.

“Senator Cruz is not going to be honest with you. He is going to make up positions and votes that I’ve never held,” O’Rourke said during the debate in San Antonio.

O’Rourke used the nickname that Trump gave Cruz during the 2016 Republican presidential campaign. “He’s dishonest,” O’Rourke said. “It’s why the president called him ‘Lyin’ Ted,’ and why the nickname stuck.”

It was a change in strategy for O’Rourke, who has been hesitant to attack Cruz while portraying himself as a post-partisan, Kennedy-esque figure who could bring Texans together.

But with polls showing him slipping farther behind just three weeks before the Nov. 6 election, and six days before early voting starts in Texas, O’Rourke had to do something.

“You have to paint in bold colors if you want people to remember what you are saying,” said Cal Jillson, a political scientist at Southern Methodist University in Dallas. “But I don’t think it changes the dynamics of the race.”

Cruz noted the more aggressive stance from O’Rourke and pointed to his fading standing in the polls.

“It’s clear Congressman O’Rourke’s pollsters have told him to come out on the attack,” Cruz said.

Texas is seen as one of the Democrats’ best chances to gain a Republican-held U.S. Senate seat in November. Democrats must pick up two seats nationwide to seize a Senate majority that would allow them to block Trump’s agenda and exercise oversight of his administration.

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Trump said he watched the debate, and weighed in on Twitter on Wednesday morning with strong praise of Cruz for securing cuts in taxes and regulations and protecting gun rights. “Beto O’Rourke, who wants higher taxes and far more regulations, is not in the same league with Ted Cruz,” Trump said.

O’ROURKE NEEDS A COMEBACK

O’Rourke will need a comeback in conservative Texas, which has not elected a Democrat to statewide office since 1994. A poll average compiled by Real Clear Politics gives Cruz a lead of 7 percentage points, and a CNN poll published on Tuesday gave Cruz a similar margin.

The Democrat’s uphill campaign has attracted national attention and a flood of financial donations. O’Rourke set a Senate record for a single three-month period with $38 million in third-quarter donations, more than triple the haul for Cruz.

Cruz has made gains in Texas by hammering O’Rourke as out of step with Texas voters because of his liberal stances, including his support for universal healthcare, a path to citizenship for illegal immigrants, and some gun-control measures.

He kept up those attacks during the debate, saying O’Rourke had repeatedly showed his willingness to align himself with the Democrats’ liberal wing over the needs of Texans.

“Every time there is a choice between left-wing national activists and the people of Texas, he goes with left-wing national activists,” Cruz said.

O’Rourke countered that Cruz was ineffective and self-serving in the Senate, more interested in his political career than in helping Texans.

“Ted Cruz is for Ted Cruz,” he said, adding the senator’s re-election campaign was “based on fear.”

Cruz said O’Rourke was eager to begin impeachment proceedings against Trump that would lead to a partisan circus. O’Rourke shot back: “It’s really interesting to hear you talk about a partisan circus after your last six years in the U.S. Senate.”

Cruz will get help next week when Trump will be top billing at a Houston campaign rally for Cruz and other Texas Republicans.

O’Rourke criticized Cruz for his unwillingness to stand up to Trump on a range of issues, and said he had failed to stop the president from pushing trade tariffs that would hurt Texas farmers and businesses.

“You are all talk and no action,” he told Cruz.