Ted Cruz, who is currently polling second in the US Republican presidential race, has a terrible personal reputation.

Cruz's colleagues in the Senate have routinely described the junior senator from Texas as being condescending, combative, and pretty much the all-around worst. People who knew him from high school and his undergraduate days at Princeton have given similar impressions.

"Everybody who knows him in the Senate hates him," conservative commentator Charles Krauthammer remarked on Thursday. "And I think hate is not an exaggeration."

Despite Cruz's rapid rise to the front of the Republican primary race, it's hard to secure the nomination for president when much of your party hates you. Cruz's brand of religious conservatism has appealed to many voters in Iowa, but whether he comes out on top when the state's caucuses begin in just 10 days remains to be seen, considering that he has yet to receive a single endorsement from a fellow senator. While Cruz's campaign is largely based on a rejection of the Washington establishment, endorsements are still important for cultivating donor support and galvanizing the party base. Since 1980, party endorsements have been the single most predictive factor for whether a candidate will have success in the early primaries, according to the book The Party Decides.

But this election season has shown that being unpopular with the establishment only serves to help candidates more than hurt them. Though Jeb Bush leads the field in endorsements, this has meant little to his flagging campaign. A lack of such support has certainly not stymied Donald Trump, who leads Cruz by 11 points in Iowa, according to latest CNN/ORC poll released on Thursday.

Cruz has set himself apart by not only managing to isolate himself from the very people who might have been his closest allies in a presidential campaign, but has gotten them to publicly despise him too. On Tuesday, Iowa Governor Terry Branstad, a Republican, said that he was rooting for Cruz's defeat. The AP reported that Republican Senator Richard Burr remarked at a recent campaign fundraiser that he would rather vote for Democratic presidential candidate Bernie Sanders, the self-described "democratic socialist" senator from Vermont, than for Cruz — and the remark was not a joke.

Wow, the highly respected Governor of Iowa just stated that 'Ted Cruz must be defeated.' Big shoker! People do not like Ted. — Donald J. Trump (@realDonaldTrump)January 19, 2016

The Republican race is looking more and more like it will be a standoff between Cruz and Trump as primary voting rapidly approaches, and many Republican lawmakers are making it clear whose side they're on.

"Between Trump and Cruz, it's not even close," Representative Peter King of New York told the Washington Post yesterday. "Cruz isn't a good guy, and he'd be impossible as president. People don't trust him. And regardless of what your concern is with Trump, he's pragmatic enough to get something done. I also don't see malice in Trump like I see with Cruz."

Cruz's unpopularity among his fellow lawmakers began almost immediately after he swept into Washington, DC in 2013 along with a wave of victorious Tea Party candidates. He quickly made it clear he had no problem being at odds with the most powerful members of his own party — which is one of the biggest no-nos in Congress.

During Cruz's first month in the Senate, he tried to block Chuck Hagel's appointment as secretary of defense by insinuating that Hagel might have accepted bribes from North Korea and Saudi Arabia. Senator Lindsey Graham (R-SC) called Cruz's conduct "out of line."

Arizona Senator John McCain, one of the highest-ranking members of the Republican Party, even called Cruz a "wacko-bird" after he filibustered John Brennan's Senate confirmation as CIA director.

Then there was the time that Cruz attempted to block Democratic Senator Dianne Feinstein's assault weapons ban by explaining to her what the Second Amendment was. She did not appreciate the condescension. "I'm not a sixth grader. I've been on this committee for 20 years," Feinstein responded. "I've studied the Constitution myself. I am reasonably well educated, and I thank you for the lecture."

Things really reached a boiling point last July when Cruz publicly accused Senate Majority Leader Mitch McConnell of lying on the Senate floor about the reauthorization of the Export-Import Bank, which Cruz opposed, prompting several Republican senators to strike back in a rare outpouring of internal party drama.

"The Senate floor has even become a place where senators have singled out colleagues by name to attack them in personal terms, to impugn their character, in blatant disregard for Senate rules," Senator Orrin Hatch (R-Ut.) said in a blistering speech directed at Cruz that did not name him directly. "Squabbling and sanctimony may be tolerated in other venues and perhaps on the campaign trail, but they have no place among colleagues in the United States Senate."

It is conventional political wisdom that a candidate needs to have at least some support from party peers in order to successfully win an election, especially a presidential one. Cruz is the only senator currently in the race who has not been endorsed by any of his fellow senators. But he clearly doesn't care about conventional political wisdom, which is one of his biggest selling points on the campaign trail.

His unpopularity inside the Beltway, or among what he has maligned as the "Washington cartel," helps him adopt the image of the outsider candidate — which is unquestionably the hottest trend this campaign season. And what better way to do that than by calling the Senate Majority Leader of your own party a liar on the Senate floor?

It is also evident that Cruz didn't develop his acerbic personality when he arrived in Washington three years ago. His classmates from college and high school say that he has pretty much always been hard to like.

Laura Calaway was in Cruz's debate club senior year of high school. "He was not well liked," Calaway told VICE News. "[There was] this weird personal disconnect. I hear that hasn't changed."

Geoffrey Cohen knew Cruz while they were both undergraduates at Princeton, and had a similar impression of him. Cohen said that he avoided the young Texan after one particularly unpleasant interaction.

"It was an argument over abortion between Ted and a female friend of mine," Cohen recalled. "Ted's style was sneering, smirking, condescending, jabbing his finger in your face — a naked desire to humiliate an opponent. No kindness, no empathy, no attempt to reach common ground."

Dear sir: Bill Clinton could be a serial eater of planets. Ted Cruz would still be an asshole. — Craig Mazin (@clmazin)January 20, 2016

Craig Mazin, Cruz's freshman-year roommate at Princeton, recently took to Twitter to fire off a series of tweets lamenting his experience knowing Cruz.

"When I met Ted in 1988, I had no word to describe him, but only because I didn't speak German. Thank you, Germans, for 'Backpfeifengesicht,' " Mazin tweeted, referring to a word that means "face that should be slapped."

Another of his tweets said, "Getting emails blaming me for not smothering Ted Cruz in his sleep in 1988. What kind of monster do you think I am? A really prescient one?"

I have 30k followers now, and all I had to do was be stuck in a room with Ted Cruz for a year. I'm sure you're all nice, but SO NOT WORTH IT — Craig Mazin (@clmazin)January 18, 2016

In December, CNN discovered a trove of 15 hours of unedited footage that was meant to be used for pro-Cruz super PAC ads and clearly not for intended for public consumption. Much of the painfully awkward footage consists of candid interviews with Cruz and his family, often interspersed with long periods of silence and coaching from Cruz and the production crew.

One memorable scene involves an interview with Cruz's mother when she declines to answer a personal question. Cruz, clearly frustrated with his mother, interrupts her to direct the shoot himself. "Look at me," he snaps. "I know it's hard, Mom."

"I'm not used to this at all," Mrs. Cruz says quietly.

This rare glimpse into a highly scripted campaign might in other circumstances make a candidate come off as endearing. But in Cruz's case, it confirms what many people familiar with him have already described.

Calaway said that the footage "kind of nails it," capturing the candidate as he tries "acting like he is a real person."

"I see him on video now and he's exactly the same," Cohen added.

Cruz's obvious intelligence, confrontational manner, and passionate right-wing ideology were evident at an early age. These defining characteristics are undoubtedly a large part of what has made him successful as a Tea Party darling and conservative firebrand.

But when these traits are combined to the extreme, as they are in Cruz, they also help explain why many people find him so unsettling and why he has become so reviled by his fellow politicians — which is no small feat in Washington, DC.