Unfortunately, the interview was diminished by Gregory's frequent repetition of a factual error regarding Cruz's inability to convince colleagues to support him.
Gregory started accurately enough, observing that Congress passed Obamacare, the Supreme Court declared it constitutional, and President Obama won a second term in office.
The mistake came whenever Cruz pointed out that Senate Democrats refuse to compromise on their unwillingness to touch Obamacare, less well-known as the Affordable Care Act, in the continuing resolution debate.
"[Y]ou don't even have the same number of folks who signed the letter who voted with you in this effort," Gregory said, referring to the letter circulated by Sen. Mike Lee, R-Utah, signed by a total of 14 senators (including Cruz) who called for Congress to defund Obamacare in the continuing resolution.
"So I'm focusing on results. Your goal and results. Where have you moved anything?" That's a great "gotcha" question, except that Gregory is wrong.
Every Republican senator voted to defund Obamacare. On the previous procedural vote that Cruz regarded as the true test of support for his strategy, he was joined by 18 other Republicans — five more than signed the letter. (Cruz's press team noted this discrepancy in a release after the interview.)
Sen. Jeff Flake, R-Ariz., missed the vote for his son's wedding, but issued a statement that he would have voted with Cruz and company.
Most importantly, of course, Cruz and Lee convinced the House Republicans to unite around the proposal, which set in motion the legislative process that now stands with Republicans calling for a delay of Obamacare and Democrats still maintaining that they won't pass any continuing resolution that touches the law.
Cruz replied at that point that the problems with Obamacare are becoming increasingly apparent, only to have Gregory interject with "facts on the ground," as he put it.
"You're making an argument," Gregory said. "I asked you a specific question based on the facts on the ground. You've made all these arguments. My goodness, you went and spoke for 21 hours to make these arguments. You haven't moved anyone."
Sen. Jeff Sessions, R-Ala., announced his decision to support Cruz and Lee during that marathon speech. "I haven't signed letters," Sessions said on the Senate floor.
"I haven't said how I was going to vote on this issue. But it was called to my attention that Senator Reid, the majority leader, flatly stated a month ago he believed in a single-payer system."
Mistakes such as Gregory's are bound to happen, especially on live TV. It might not be worth pointing out, except that Gregory returned to that false statistic to deflect every successive question from Cruz about Democratic unwillingness to comprise on the continuing resolution.
"Can you tell me any movement the Democrats have had whatsoever, David?" Cruz asked.
"What have you done to make him move, other than disrupt, your critics would say?" Gregory replied, then repeating his mistake.
"Because as I outlined before, you lost ground from even this summer on the position of getting people to vote with you. You lost ground from that position. And you haven't persuaded one Democrat. You've got to have Democrats if you're going to overturn this thing."
Gregory later quoted a conservative columnist George Will's criticism of the attempt to use the continuing resolution to defund Obamacare before asking, apropos of the column, if Cruz is "more moralist than legislator?"
Cruz pointed to a detail about Will's column that Gregory apparently overlooked. "I'm pretty sure George Will, in that column, argued that what we should be doing is delaying Obamacare, which is exactly what the House of Representatives just voted to do," he said.
Will was a little more specific -- he wanted a delay of Obamacare's individual mandate. House Republicans can attach to the continuing resolution that funds the government, and then to the increase in the debt ceiling, two provisions:
"Preservation of the ACA requirement -- lawlessly disregarded by the administration -- that members of Congress and their staffs must experience the full enjoyment of the ACA without special, ameliorating subsidies," Will wrote. And a one-year delay of the ACA's individual mandate.
"By vetoing legislation because of these provisions, and by having his vetoes sustained by congressional Democrats, Obama will underscore Democrats’ devotion: Devotion to self-dealing by the political class, and to the principle that only powerful interests (businesses), not mere citizens, can delay the privilege of complying with the ACA," he also wrote.
House Republicans voted to delay all of Obamacare, rather than just the individual mandate. They reportedly intend to respond to Democratic opposition to such a measure by voting to force Congress onto the health care exchanges, which many lawmakers oppose.