WASHINGTON - Democrat Beto O'Rourke, trying furiously to unseat Republican Sen. Ted Cruz, sought to define his differences with his opponent Thursday during a nationally televised town hall just weeks before the midterm elections, but softened the tone he has used in recent days.

  • O’Rourke suggested attack "Lyin' Ted" at debate came in heat of the moment
  • Despite national spotlight, record campaigns, remains behind Cruz
  • Says he would impeach President Trump           

The Democratic challenger made headlines earlier this week for calling Cruz dishonest and saying at a debate that President Trump was right to refer to him during the 2016 presidential campaign as “Lyin’ Ted.”

O’Rourke, who has emphasized since the start of his campaign that he is running on a positive message, suggested Thursday that he regretted using the attack line and said “I took a step too far” and that he didn’t feel “totally comfortable” with his choice of words.

“I don’t know that that’s the way that I want to be talking in this campaign,” O’Rourke said in a nationally televised CNN town hall in the U.S.-Mexico border city of McAllen. “I decided that, you could spend the rest of the debate responding to every single dishonest thing that he’d said, or I could make sure that everyone understands what he’s doing,” he added.

O’Rourke is short on time to catch-up to Cruz, with a wave of public polls showing the Democrat is fading, on course to lose in November. Cruz was unable to participate in the event due to scheduling conflicts.

The contrast between the two candidates is striking: O’Rourke is running as a progressive and Cruz tilts toward conservative Tea Party activism.

The Democrat was pressed during the event on his stances on health care, gun ownership and immigration – all issues where he has stark differences with Cruz.

He promoted the idea of expanding health care to more Americans through Medicare and said he was proud to have an F grade from the National Rifle Association, the group has given Cruz an A, saying he did not want to take guns away from law abiding citizens but does favor stricter background checks.

"We need someone who could not care less about what the NRA or the gun lobby or any other political action committee thinks," he said.

Cruz has attacked O’Rourke’s stance on border security, casting him as soft on an issue crucially important to the state.

"I'm not in favor of open borders," O’Rourke said, defending his policies and arguing that he wants a comprehensive immigration plan but not the wall favored by Trump.

O’Rourke also offered a message aimed at immigrants and Hispanic voters in the state. He called for the immediate reunification of migrant families separated at the border as part of the Trump administration’s “zero tolerance” policy and said there should be a path to citizenship for immigrants brought to the country illegally as children – the so-called dreamers.

O’Rourke pushed back against Republicans claim that he wants to legalize all drugs.

"To be clear, I don't want to legalize narcotics,” he said. “I do think we should end the prohibition on marijuana and effectively control and regulate its sale."

O’Rourke said that he believes he can work with Trump on areas where they agree, but he did not back down from his earlier statement that he would vote to impeach the president.

“I would liken impeachment to an indictment. There is enough there to proceed to a trial,” he said.

Texas is a closely watched race, one Republicans unexpectedly focused on in recent weeks. At stake in the midterm elections, the balance of power in Congress and the states, as both parties attempt to further shape their identities in the Trump era. Democrats are well positioned to take control of the House, but the battle for the Senate favors Republicans.

Even if he loses the race, O'Rourke has made a name for himself as a politician able to excite voters, live and on social media.

O’Rourke has amassed a staggering amount of money — raising a record $38 million in the most recent reporting period, with a majority of his donations including small, individual amounts — showing the interest his candidacy has attracted.

Gaining attention across the country has prompted speculation he will run for president, although O’Rourke shot the idea down Thursday, using his young kids as the reason. He said at this time, the answer is “a definitive no” when it comes to a possible White House bid.

While O’Rourke’s campaign attracts considerable national attention, Texas hasn't elected a Democrat to statewide office in nearly 25 years. He is a three-term congressman from El Paso who gave up his seat to challenge Cruz, the Republican incumbent first elected in 2012.

Asked what he plans to do if he loses to Cruz, O’Rourke said: “If I don’t win, we’re back in El Paso.”