Their bitter 2016 rivalry was all but forgotten at a Houston rally as Trump turns to a narrative of fear and falsehoods to shore up Republican control of Congress

Two years ago they were sworn enemies. But on Monday night, with a handshake, a hug and a sycophantic prediction that “in 2020, Donald Trump will be overwhelmingly reelected as president of the United States,” Ted Cruz made peace with the president – whose help he badly needs in the fight for his Texas Senate seat.

Desperate times call for desperate measures. Cruz is coming under extreme pressure from his Democratic challenger, Beto O’Rourke, while Trump, troubled by the prospect of a blue wave in November’s midterm elections, is trying to shore up Republican control of Congress.

Americans urged to vote 'like lives depend on it' after reports of Trump anti-trans push Read more

So in Houston on Monday, the pair’s toxic relationship of 2016 was forgotten. And Trump – the man who coined the phrase “Lyin’ Ted” – bestowed a new epithet upon his old foe: “Beautiful Ted”.

“God bless Texas, and God bless President Donald Trump,” Ted Cruz declared at a rally in a Houston basketball arena, as Trump turned to an increasingly fantastical narrative of fear and falsehoods, making unsubstantiated claims that Democrats were “encouraging millions of illegal aliens to break our laws, violate our borders and overwhelm our nation”.

Play Video 2:23 Obama attacks Trump at midterm rally without ever naming him – video

This was the first of four scheduled Trump rallies this week. He dubbed O’Rourke “a stone-cold phony” in a more than hour-long speech that alighted on many of his favourite topics: immigration, tax cuts, border security, terrorism, jobs, the economy, the supreme court, healthcare, the military, fossil fuels – and globalisation.

“I’m a nationalist, OK? I’m a nationalist,” he said. “Use that word.”

Trump claimed, without citing evidence, that the northbound “caravan” of central American migrants is “an assault on our country and in that caravan you have some very bad people”.

Trump described Cruz as “a man who has become a really good friend of mine”, a marked contrast to 2016, when he hurled everything at him.

Then, Trump called Cruz a “nasty guy”, “the single biggest liar” and “so dishonest”. He threatened to “spill the beans” on Cruz’s wife, Heidi (whatever that meant), and retweeted an unflattering photo of her along with an image of his own wife, Melania, a former model. Trump also cited a baseless conspiracy theory linking Cruz’s father to the assassination of John F Kennedy.

Cruz in 2016 returned fire. He called Trump a “sniveling coward”, a “pathological liar”, “utterly amoral”, “a big, loud, New York bully”, “consistently disgraceful”, a “train wreck”, a “serial philanderer” and “a narcissist at a level I don’t think this country’s ever seen”.

But two years on, Cruz desperately needs Trump to help quell the threat of O’Rourke. The 46-year-old Democratic congressman from El Paso was also in Houston on Monday as early voting in the state began, drawing tens of thousands to make their choice well ahead of the mid-terms on 6 November.

O’Rourke is a charismatic rising star who has greatly out-raised Cruz, picking up a record-breaking $38m in donations in three months. He also enjoys strong grassroots support.

Facebook Twitter Pinterest Beto O’Rourke interviewed by a young supporter. Photograph: Loren Elliott/AFP/Getty Images

However, Trump loyalists were out in force at the Toyota Center – up to 19,000 inside and several thousand more watching outside. “We need all the help we can get for Ted,” said Jose Martinez, almost inaudibly from behind a Stars and Stripes face mask.

The 50-year-old had travelled more than 300 miles to Houston and sported a “Re-elect Trump 2020, Make Liberals Cry Again” T-shirt. The spat between Cruz and Trump, he said, was just electioneering: “The name of the game – but once it’s over we unite.”

A large and lively crowd booed and cheered on cue. Some Trump fans had camped out to ensure their places and the campaign claimed that 100,000 tickets were requested.

Sharon Alford, standing outside a camper van with a giant pro-Cruz banner on the side, agreed. “That’s called politics,” she said. “He’s there to represent us so he needs to put his sentiments aside and go and do what he was elected to do.”

Alford was initially a reluctant Trump supporter after Cruz’s loss, but said: “I have since just fallen in love with Trump. His motto is ‘promises made, promises kept’ and by golly, that’s exactly what he’s done. If it wasn’t for the Democrats we’d have a wall now.”

The atmosphere recalled the Super Bowl fan festival staged in Houston last year: music, big screens, excited supporters clad in red. This time the designs on T-shirts hawked by unofficial street vendors were not beatific images of the quarterback Tom Brady, but mock-ups depicting the occupant of the White House urinating on the CNN logo and as “THE DEPORTER”, standing in front of a Border Patrol SUV brandishing a gun.

In Las Vegas, meanwhile, Barack Obama was in a different sports arena, with an aggressive message of his own at a Democratic rally that was focused on getting out the vote, particularly with young and Latino people.

“You wouldn’t let your grandmother decide what you should wear. You would not allow your parents to decide what’s on your playlist,” Barack Obama told the crowd. “So why would you give up your power whether or not we do something about climate change?”

Although he didn’t mention Trump by name, the former president warned of the rise of demagogues who sought to hold onto power by dividing people. Obama targeted congressional Republicans, specifically the Senate majority leader Mitch McConnell, whose name was greeted by boos. “Don’t boo, vote,” Obama said. “Booing doesn’t do anything. Booing doesn’t help, voting helps!”

Facebook Twitter Pinterest Barack Obama greets supporters after speaking in Las Vegas. Photograph: Ethan Miller/Getty Images

Obama ended by emphasising healthcare, specifically guaranteeing coverage for those with pre-existing conditions, which has been perhaps the defining Democratic issue of the midterms. “I know you can bet on anything here in Vegas, but you don’t want to bet that Republicans are actually going to protect your healthcare,” he said.

In the Texas race, Cruz has repeatedly pointed to O’Rourke’s support of universal healthcare as supposed evidence of the Democrat’s socialist tendencies. For most of his campaign, O’Rourke barely mentioned Cruz or Trump, preferring to stress a positive message of hope and unity.

But in recent weeks it became apparent that projecting optimism and inclusivity is not a winning electoral strategy in Texas. O’Rourke’s momentum may have stalled; recent polls indicate a Cruz lead of between five and nine points.

O’Rourke fought back in a debate last week. He was notably more aggressive and even quoted Trump, saying of Cruz: “He’s dishonest. That’s why the president called him ‘Lyin’ Ted’, and it’s why the nickname stuck - because it’s true.”