There is no doubt that leading establishment Republicans hate Ted Cruz, to the point that some are trying to beat him by praising instead Donald Trump, a reality TV and professional wrestling personality with four bankruptcies, two divorces and a long history of giving big money to Democrats, including his likely opponent, Hillary Clinton. Cruz’s congressional colleagues aren’t even willing to assert that Cruz is eligible for the presidency; when John McCain, who like Cruz was born outside the U.S., ran for president, Republicans in Congress passed a resolution asserting his eligibility for office. No such routine courtesy gesture was forthcoming for Cruz.

The question is why. What is it about Ted Cruz that will get someone like Bob Dole, who once wrote Reagan off as an extremist, to pump for Trump instead? There are several possible theories for why this is true, which are not mutually exclusive.

His Colleagues Know Cruz as Self-Serving, Arrogant, Grandstanding and Uncollegial

In support of this explanation, Molly Ball of The Atlantic cites several incidents where Senate colleagues claim that he put throwing red meat to his donor and activist base above loyalty to fellow senators, even friends. Among several similar incidents, Ball noted that Cruz’s personal friend, Sen. Mike Lee of Utah, sponsored a criminal sentencing reform with significant bipartisan support.

When Lee brought up his bill in the committee hearing, he wasn’t sure if he’d have Cruz’s support. But he certainly didn’t anticipate what came next.

Cruz attacked the bill as dangerous and politically poisonous. He said it would lead to more than 7,000 federal prisoners let out on the street. “I for one, at a time when police officers across this country are under assault right now, being vilified right now, when we’re seeing violent crime spiking in our cities across the country, I think it would be a serious mistake for the Senate to pass legislation providing for 7,082 criminals to be released early,” he said. The bill, he claimed, “could result in more violent criminals being let out on the streets, and potentially more lives being lost.” Cruz went on to warn his fellow senators that if they voted for the bill, they would imperil their careers.

Cruz has also been connected with several grassroots, Tea Party groups that raise funds by periodically savaging Republican leaders in Congress, and dozens of Republican senators and congressmen, for “caving” on conservative priorities from immigration to Obamacare.

Jonathan Bernstein of the Chicago Tribune echoes Ball’s assessment, noting “most of the anti-Cruz fervor seems to be coming from people who have worked with him, which mostly means those in Washington.”

Caroline Bankoff, in New York magazine, observes:

While Cruz’s “insufferable designated driver” persona might appeal to some of the American electorate, his Republican colleagues — the people who have to deal with him in the cold, sober light of day — can’t stand it. This became especially apparent in the last six months, as Senate Majority Leader Mitch McConnell and his fellow Republicans have gone out of their way to thwart Cruz’s attempts to hold roll-call votes (generally not a hard thing to do) and shut down the government over Planned Parenthood funding.

In 2013, at Cruz’s urging, House tea-partiers inserted a provision repealing the Affordable Care Act in the next year’s spending bill. This effort to kill Obamacare was doomed from the start — the majority-Democrat Senate, not to mention President Obama, wouldn’t approve it — but that didn’t stop Cruz from insisting the plan could work. While the resulting 16-day government shutdown was an image disaster for the GOP in general, it made Cruz look like a hero to tea-party voters. Lindsey Graham has said of Cruz: “He plays into the frustrations and passions of good people and creates narratives that don’t exist at the expense of others.”

Not everyone who has worked with Cruz evaluates him this way. Theodore Gebhard, who served with Cruz for two years at the Federal Trade Commission, writes at The American Thinker:

I found Ted to be very easy to work with. I never knew him to tout his own résumé, talk down to anyone, or insist on deference to his position. To the contrary, I knew him to be consistently pleasant, generous with his time, and most importantly, always respectful of others’ views and work-product. I remember, for example, that Ted often dropped into my office to follow up on some comment or idea that I had offered during an earlier task force meeting. Those meetings generally permitted only limited discussion because of the number of people present, and Ted wanted to explore my thinking further. Unlike many persons holding titles in government, it never occurred to Ted that, because of his higher position as head of the task force, protocol would demand that I be called into his office. Such ego-driven attachment to hierarchy never mattered to Ted. To the contrary, he was only interested in getting the best ideas out of the people around him.

Certainly Cruz’s willingness to make enemies in Congress has served him well, catapulting him as a freshman senator to second place in the GOP presidential primary field, while legislators and governors with extensive resumes, such as Wisconsin Gov. Scott Walker and Sen. Santorum were left in the dust.

And there’s another possible explanation of Cruz’s blank unwillingness to play well with others on the Republican congressional team.

Ted Cruz Thinks the Republican Party Has Been Scamming Its Voters

On this theory, Ted Cruz defeated a squishy centrist Republican lieutenant governor in the primary and went on to win in Texas in 2012 as part of a wave of populist rebellion against President Obama, whose foreign policy, health care plan, judicial appointments and refusal to enforce immigration law enraged the same conservatives who had been uninspired by Republican presidential nominees John McCain and Mitt Romney. Republican candidates across the country ran for election or re-election with promises that they would push back against Obama, using Congress’ power of the purse to rein in his leftist initiatives.

When Cruz arrived in Congress, he seems to have taken seriously the language he used in winning the election, and expected his fellow Republicans to do the same. And he was bitterly disappointed — along with many voters, by repeated Republican refusals to risk a government shutdown, which is, as students of U.S. history will remember, the key means that our Founders put into the Constitution to prevent a president wielding arbitrary power. They were thinking of Kings George III and Charles I, and Louis XIV of France. Given that Obama is using executive power to grant de facto amnesties, restrict the sale of handguns and import unvetted Syrian refugees into America, many conservatives feel that only one side is playing hardball, playing to win — the Democrats. The Republicans seem content to wave liberal policies through while in office, rant against them during election campaigns and stump for bland, centrist presidential candidates who lose — like Bob Dole, John McCain and Mitt Romney.

Joseph Rago, in The Wall Street Journal quotes Cruz to this effect:

“Our representatives aren’t representing us. They’re representing large corporations and lobbyists rather than the American people,” Mr. Cruz declared at the Heritage Foundation last June. The “Republican leadership,” he said in a Senate floor speech in September, “will not fight for a single priority we promised the voters we would fight for when we were campaigning less than a year ago.”

If this second explanation is correct, Cruz’s behavior toward his colleagues is the fruit not of personal arrogance but of disappointment, even righteous indignation — the reaction of an honest rookie cop who finds out that his fellow officers, even his sergeant, are cowards, defeatists, or are on the take.