Video report by ITV News Correspondent Emma Murphy
Texas Senator Ted Cruz has admitted his family holiday to Mexico was "obviously a mistake" following an uproar over his absence during severe snowstorms, power cuts and water supply issues in the state.
The Republican senator travelled out of the country with his family as hundreds and thousands of his constituents faced power cuts and treacherous conditions which caused the deaths of at least 56 people.
Utilities from Minnesota to Texas used rolling blackouts to ease strained power grids, while other outages were caused by the extreme weather.
To add to the misery, the extreme cold caused water lines to freeze and damaged infrastructure and pipes, and many people were left without safe drinking water even after power returned.
Authorities ordered seven million people, a quarter of the population in Texas, to boil tap water before drinking it.
Mr Cruz told reporters that he began second-guessing the trip the moment he got on the plane on Wednesday.
He said he returned to the USA on Thursday night because he realised he needed to be in Texas and that he had originally been scheduled to stay in Mexico through the weekend.
In an earlier statement, he said he accompanied his family to Cancun after his daughters asked to go on a trip with friends, given that school was cancelled for the week.
The trip drew criticism from leaders in both parties and was seen as potentially damaging to his future political ambitions which could include a second presidential run in 2024.
Mr Cruz lost to Donald Trump in his bid to be the Republican Party's presidential candidate in 2016.
Mr Cruz said: "I didn’t want all the screaming and yelling about this trip to distract even one moment from the real issues that I think Texans care about, which is keeping all of our families safe.
“It was obviously a mistake, and in hindsight, I wouldn’t have done it,” he said.
In his earlier statement, Mr Cruz said he flew with his family because he wanted "to be a good dad", adding: "My staff and I are in constant communication with state and local leaders to get to the bottom of what happened in Texas.
"We want our power back, our water on, and our homes warm."
The incident has intensified political backlash that erupted after he emerged as a leader in former president Trump’s push to overturn the results of the November election.
Billboards calling for his resignation stood along Texas highways earlier in the month.
Even the state Republican Party chair declined to come to Mr Cruz’s defence on Thursday.
"That’s something that he has to answer to his constituents about," Texas GOP Chair Allen West said when asked whether Cruz’s travel was appropriate.
"I’m here trying to take care of my family and look after my friends and others that are still without power," Mr West said.
"That’s my focus."
Hundreds of thousands of people in Texas woke up on Thursday to a fourth day without power, and a water crisis was unfolding after winter storms wreaked havoc on the state’s power grid and utilities.