WASHINGTON — El Paso Rep. Beto O'Rourke isn't betting his bid for toppling Sen. Ted Cruz entirely on backlash against President Donald Trump, or probes of Russian ties to his campaign, or his efforts to ban Muslim visitors, or deport young immigrants, or wall off the southern border.

But he isn't shy about raising those topics and using them to tar the polarizing senator for his coziness with an even more polarizing figure in the White House.

This being Texas, where Democrats haven't won a statewide contest since 1994, stoking misgivings about Trump may be O'Rourke's best shot at stopping Cruz from winning a second term next year.

"He represents the most dangerous threat that our democracy has faced in my lifetime. I don't think he's fit to be our president," he said over coffee at a cafe near the Capitol, warning that history will scrutinize this era. "Will this be the chapter that describes where America after 230 years lost her democracy? We are all accountable for what we do or fail to do."

Democrats nationwide will try to use Trump as an albatross in the 2018 elections. For O'Rourke, it's an irresistible line of attack, since both the president and Cruz are, to a rare degree, love-him-or-hate-him politicians.

His indictment of Cruz centers on several points: the senator's naked ambition, his crusade against Obamacare, and an abrasive style that keeps him from delivering for Texans.

"He has been unable to form relationships that will allow him to be productive and act on our state's priorities and agenda. And Texas deserves better than that," said O'Rourke, a former El Paso councilman who's giving up a safe House seat in his bid to oust Cruz.

The senator's campaign declined to address the missives against him, or the effort to use Trump as a bludgeon.

O'Rourke's assessments of Trump echo some of Cruz's own rhetoric in the heat of the 2016 presidential primaries, when he called Trump a "pathological liar" and a "narcissist" too dangerous to entrust with control of a nuclear arsenal. He's been a team player since explicitly declaring his support for Trump six weeks before Election Day.

O'Rourke and Cruz were both elected in 2012. The congressman just turned 45. Cruz will be 47 in December.

Cruz hasn't done much overt campaigning yet. Assuming he survives a primary against a handful of underfunded and little known challengers, he'll head into November 2018 with plenty of advantages.

That list includes the crusades O'Rourke calls misguided. Cruz's scrapes with the GOP establishment have endeared him to many voters, even if they've left him unpopular in the Senate.

At the moment, Democrats lack a challenger for Gov. Greg Abbott, who won his last race by a whopping 20 percentage points. There's no sign the party's national Senate campaign apparatus will divert significant sums to Texas next year; retaking the Senate will hinge on states where campaigns cost far less and offer much better odds.

All of that leaves O'Rourke on his own.

He has some tailwinds, though.

Cruz is deeply unpopular among voters who don't identify as ardent Republicans.

Setbacks are typical for a president's party in the elections two years into his term.

And even though the GOP grip on Texas remains firm, Trump carried the state by just 9 percentage points — a much tighter margin than most GOP presidential nominees and other statewide candidates. That suggests an opening for O'Rourke.

President Donald Trump talks with Sen. Ted Cruz during a White House event on June 5. (Mark Wilson / Getty Images)

The more tightly he ties Cruz with the president, the better.

So he hammers Trump for pursuing a Muslim ban and a border wall, even filing legislation last week that would bar government land seizures for the project. He decries Trump for "denigration and vilification of the press" and occasionally encouraging violence against journalists, for firing an FBI director and trying to pressure an attorney general to stop the Russia investigation.

"His attempt to destroy the norms, the civility, and in some ways the very foundations of rule of law in this country ... his encouragement of neo-Nazis and white supremacists, his description of Mexican immigrants as rapists and criminals, his mockery of somebody with physical disabilities — this can't be us," O'Rourke said.

O'Rourke has echoed calls by Democrats such as Houston Rep. Al Green for impeachment. But he wants the special counsel probe led by former FBI director Robert Mueller to play out first.

"The only way it should happen is that the facts are so compelling that a Republican colleague of mine can go back to her district or his district and explain to their constituents how they were able to vote to impeach the president of their own party," he said, adding, "That set of conditions doesn't exist today."

Implicit in the critique is a reminder that while he would defy this president from a perch in the Senate, Cruz has rarely spoken out against Trump since dropping out of the 2016 presidential race and nearly always stands by him.

But that's only the start of O'Rourke's indictment.

Cruz made his first political appearance in South Carolina, the third state on the 2016 presidential nomination circuit, just six months after winning a Senate seat, his first elected office.

"He put his career before the people of Texas," O'Rourke said. "When I go to Waco or I go to Sherman, or I'm in Wichita Falls or I'm in Canyon or I'm in Fort Stockton," Texans laugh when he asks them what Cruz said the last time he held a town hall event there.

"He has not been responsible or accountable. He wasn't in Sherman, Texas. He was in Des Moines, or he was in New Hampshire or South Carolina or Nevada, at a time when he should have been serving and being held accountable by the people of Texas," he said.

Cruz and his aides have bristled at allegations that he has been aloof. But his appearances are typically invitation-only, independent analysis shows, for employees of a particular company or a select civic group. That, said his rival, is no substitute for a "no-holds-barred town hall, not filtered or curated or screened."

O'Rourke also likes to point to the 16-day government shutdown in fall 2013, which Cruz engineered as part of a crusade with House conservatives who shared his desire to defund the Affordable Care Act.

Cruz never expressed regret over the shutdown, defending his tactics as justified to prod Congress to abandon a disastrous policy. During the 2016 primaries, he touted the episode as evidence that he'll fight harder than rivals for voters' interests.

The tactic failed to achieve its purported aim, though, and GOP leaders were livid. Many viewed it as grandstanding. The House speaker at the time, John Boehner, later called Cruz a "jackass" and "Lucifer in the flesh."

"He shut down the government at extraordinary cost to this country and to his constituents," O'Rourke said. And for what? If derailing the Affordable Care Act was worth such extreme measures, why has Cruz come up "empty-handed" on the front for five years?

"He had an opportunity to create or propose or build a consensus around an alternative to Obamacare. He was absolutely unable to do it," O'Rourke said. "His party now controls every lever of power. He's ally to the president. If Obamacare were the singular threat to the American people, where is his ability to deliver that?"