Sen. Ted Cruz is still the favorite in his race for re-election. He's got plenty of cash on hand, has yet to trail his challenger, El Paso U.S. Rep. Beto O'Rourke, in any publicly released poll and, according to the number-crunchers at Nate Silver's FiveThirtyEight, has about a 66 percent chance to hold onto the seat he won in 2012.

All that being said, there are signs, increasing in frequency over the last month or so, that O'Rourke is picking up steam. The Democratic challenger, while he's yet to take the lead in any poll, is dominating the narrative of the race, making the idea of a Democrat winning a statewide race in Texas for the first time in two decades seem, at least, possible.

As Cruz and O'Rourke get set to embark on the biggest week of their campaigns thus far, culminating in Friday night's debate in Dallas, let's look at the recent signs that O'Rourke's arrow is pointing up.

1. The polls. — Since the beginning of July, the headline numbers for polls in the Cruz-O'Rourke race have remained largely the same. The two candidates, according to the surveys, are close, with Cruz maintaining a lead somewhere in the low single digits.

Despite the apparent stubbornness in the bottom-line results for O'Rourke, the challenger has a couple of reasons to take heart. First, he's remained competitive in polls with highly Republican samples, showing that he can be competitive, even in an election in which far more self-identified Republicans show up than Democrats — like a Texas midterm. Second, O'Rourke has maintained his proximity to Cruz even as former Dallas County Sheriff Lupe Valdez, Texas Democrats' nominee for governor, has lost touch with incumbent Greg Abbott in that race. In recent surveys by NBC News and Quinnipiac University, Valdez trailed Abbott by 19 and 13 points respectively; according to those same polls, O'Rourke trailed Cruz by 4 and 6 points.

According to experts like Rice University's Mark Jones, one of the biggest hurdles to election for O'Rourke is finding Abbott voters willing to split their tickets and vote for a Democrat against Cruz. Recent polls suggest those voters exist.

2. The crowds. — While crowd size isn't everything, O'Rourke continues to draw thousands of people to rallies in some of the reddest parts of a red state. On Saturday, the candidate drew standing-room only crowds at events in Collin and Denton counties, both of which have been dominated by Republicans since the '80s. O'Rourke events, often literally, are more like rock concerts than political gatherings, befitting for a candidate who played in punk bands as a teenager.

O'Rourke started the race with limited name recognition, thanks in large part to El Paso's isolation from the rest of the state. That's not a problem anymore. He's held events in each of Texas' 254 counties and continues to have big turnouts on his second, third or 13th visits. Enthusiasm drives turnout, and O'Rourke's campaign has plenty of it.

Every man, woman, and child should be able to see a doctor, afford their prescriptions, and get the care they need to live to their full potential. pic.twitter.com/9MHIlIjhmW — Beto O'Rourke (@BetoORourke) September 16, 2018

3. Likability. — Even when Texas Republicans think they've found grounds on which to attack O'Rourke, they end up drawing negative contrasts between the Democrat and Cruz. Late last month, the Texas GOP published a series of tweets attacking O'Rourke for, among other things, a DWI arrest for which he'd already repeatedly and publicly expressed contrition, the fact that O'Rourke appeared in a dress on the cover of a 7-inch album pressed by one of his bands, Foss, and his ride on a skateboard in a Whataburger parking lot. The tweets lit the internet up, but not in the way the GOP hoped. Dozens of tweets supporting O'Rourke's candidacy and general sexiness poured in, leading one to wonder if Texas Republicans had any prior experience with Twitter's audience.

here’s what ted cruz and beto o’rourke were doing to unwind during roughly the same period pic.twitter.com/yxsXGaaF0y — Ashley Feinberg (@ashleyfeinberg) August 29, 2018

4. O'Rourke keeps going viral. — First, it was the national anthem. In August, an audience member at an O'Rourke town hall asked the candidate about NFL players protesting during the anthem. O'Rourke gave a lengthy, nuanced response in support of Colin Kaepernick and other demonstrators. (O'Rourke's statement is in its entirety below, because the whole thing is worth reading.)

My short answer is no, I don’t think it’s disrespectful. Here’s my longer answer, but I’m gonna try to make sure that I get this right because I think it’s a really important question. And reasonable people can disagree on this issue, let’s begin there. And it makes them no less American to come down on a different conclusion on this issue, right? You’re every bit as American all the same. But I’m reminded that somebody mentioned reading the Taylor Branch book — you did — Parting the Waters: [America] in the King Years. And when you read that book and find out what Dr. King and this nonviolent, peaceful movement to secure better — because they didn’t get full — civil rights for their fellow Americans, the challenges that they face — those who died in Philadelphia, Mississippi, for the crime of trying to be a man, trying to be a woman, in this country, the young girls who died in the church bombing, those who were beaten within an inch of their life crossing the Edmund Pettus Bridge in Selma, Alabama, with John Lewis, those who were punched in the face, spat upon, dragged out by their collar at the Woolworth lunch counter for sitting with white people at that same lunch counter, in the same country where their fathers may have bled the same blood on the battlefields of Omaha Beach or Okinawa or anywhere that anyone ever served this country. The freedoms that we have were purchased not just by those in uniform, and they definitely were. But also by those who took their lives into their hands riding those Greyhound buses, the freedom riders in the deep South in the 1960s who knew full well that they would be arrested, and they were, serving time in the Mississippi State Penitentiary. Rosa Parks getting from the back of the bus to the front of the bus. Peaceful, nonviolent protests, including taking a knee at a football game to point out that black men, unarmed; black teenagers, unarmed; and black children, unarmed, are being killed at a frightening level right now, including by members of law enforcement, without accountability and without justice. And this problem — as grave as it is — is not gonna fix itself, and they’re frustrated, frankly, with people like me and those in positions of public trust and power who have been unable to resolve this or bring justice for what has been done and to stop it from continuing to happen in this country. And so nonviolently, peacefully, while the eyes of this country are watching these games, they take a knee to bring our attention and our focus to this problem and ensure that we fix it. That is why they’re doing it, and I can think of nothing more American than to peacefully stand up or take a knee for your rights anytime, anywhere, anyplace.

After NowThis released a video of O'Rourke's mini-speech, his comments went viral, drawing positive attention around the state and nationally. The Cruz campaign tried to fight back, heavily editing a similarly lengthy O'Rourke response at another event to make it appear he supported flag burning, but ended up shooting itself in the foot.

O'Rourke's ridden the wave of goodwill to several national TV appearances, including a highly publicized spot on Ellen DeGeneres' talk show.

Amid all the attention, several Republican political action committees, including the Club for Growth, have sprung into action to defend Cruz, showing that national Republicans are at least worried enough to think Cruz could use the extra help.

5. Debates. — Friday evening, the O'Rourke and Cruz campaigns announced that the two candidates will face off in debates three times between Friday and election day. While three is only half of the six debates O'Rourke asked for initially, he did score several concessions from the Cruz campaign on the days of the week on which the debates will be held — Cruz wanted every debate to be on Friday night, now the second and third debates are scheduled for a Sunday and a Tuesday — and the format in which they'll be conducted. Rather than the candidates being stuck behind a podium for every debate, one of the showdowns will now be a town hall, something that seemingly favors the personable O'Rourke.

If Cruz didn't think he needed to change the race, he wouldn't have agreed to three debates. Six years ago, Cruz had just a single debate with Democratic challenger Paul Sadler, and none of the senator's fellow Republicans running for statewide office have agreed to more than a single debate with their Democratic opponents.