The success of Senate hopeful Beto O'Rourke, who needs a cross section of Texas voters to beat incumbent Republican Ted Cruz in November, hinges on voters from disparate backgrounds finding common ground in his message.

O'Rourke has been deft at pushing delicate positions important to his Democratic Party base, while not driving away Republicans and independents that are considering choosing him over Cruz.

His high-wire act was on display Friday in Dallas during his rally at the Good Street Baptist Church, where he sought to shore up his support with black voters.

There was a moment during O'Rourke's fiery speech when some Democrats wondered if their party's savior was tone deaf.

O'Rourke praised the marksmanship of his late uncle, who was a deputy sheriff in El Paso County. He then talked about how law enforcement officials have the power to use lethal force, and that they should "hold themselves accountable to the very high standards we set."

"I'm grateful for everyone who has served in that capacity," O'Rourke said, muting the otherwise boisterous crowd.

Dallas has been rocked by the shooting death of Botham Jean, a black man gunned down by white Dallas police Officer Amber Guyger after she entered his apartment. She said she confused his residence for hers.

Most in the congregation were not in the mood for tributes to police officers. Members of his Dallas team sensed a restlessness in the crowd and used hand gestures to reassure folks that their locally and nationally hyped candidate was sensitive to issues paramount to black voters.

Then O'Rourke got on a roll, unleashing blistering criticism of the Jean shooting and its investigation.

"How can it be, in this day and age, in this very year, in this community, that a young man, African-American, in his own apartment, is shot and killed by a police officer," O'Rourke said, as the crowd roared with emotion. "And when we all want justice and the facts and the information to make an informed decision, what's released to the public? That he had a small amount of marijuana in his kitchen."

O'Rourke got a standing ovation and many in the pews yelled with approval. Good Street's pastor, Eddie L. Jenkins, passed O'Rourke a tissue to wipe his brow. That's what church deacons and associate ministers do when a preacher is hitting his stride.

O’Rourke achieved two objectives. He stayed true to the memory of his Uncle Raymond by honoring law enforcement officials, while decrying the shootings of unarmed African-Americans that's occurring across the nation.

As sweat stained his light blue shirt, O'Rourke backed it all up with an emotional plea for Texans to come together and lead the nation in solving problems related to immigration, criminal justice, health care, education and the school-to-prison pipeline that has devastated black families.

U.S. Representative Beto O'Rourke campaigns in Dallas, Texas, on September 14, 2018. - O'Rourke is the Democratic challenger for the U.S. Senate seat currently held by U.S. Senator Ted Cruz . (LAURA BUCKMAN / Getty Images)

But O'Rourke is revving up his Democratic Party base by addressing issues that could sink him with conservative voters. It includes his earlier pronouncement that there's "nothing more American" than NFL players protesting against police violence by kneeling during the national anthem.

It's a dangerous dance as the congressman's views on these matters threaten his ability to win over Republicans and other voters outside the Democratic Party base.

The Cruz campaign has already started running television ads critical of O'Rourke's comments about the NFL protests.

"In November, where will you stand?" a narrator asks voters at the end of the ad.

More attacks are on the way, as super PACs backing Cruz are expected to begin a blistering ad campaign against O'Rourke, who says he will continue a positive campaign as Cruz mounts an offensive.

Most Texas Republicans, and even many Democrats, are turned off by NFL players kneeling during the anthem. O'Rourke is banking that the majority of voters will accept that it's their American right to do so.

Sen. Ted Cruz waves to the crowd after addressing supporters during a campaign event at Babes Chicken Dinner House on Tuesday, Aug. 14, 2018, in Arlington, Texas. (Smiley N. Pool / Staff Photographer)

O'Rourke scoffs at traditional political science, and he's managed to be the same person in all of the 254 counties he's visited.

With the exception of his take on the Jean shooting, his remarks in Dallas were nearly identical to the speeches he's delivered in Richardson and Plano. Everybody is getting the same message.

For his part, Cruz has been consistent in his unabashed conservatism.

If O'Rourke survives Cruz's upcoming onslaught and is able to win in November, he'll reshape how politicians approach campaigns.

If he loses, he'll be able to take comfort that he didn't sell out.