Significant daylight has emerged between the Senate's dynamic conservative duo. Once shoulder to shoulder on healthcare reform with his longtime friend, Utah Sen. Mike Lee, Texas Sen. Ted Cruz has decided to go his own way.

At the outset of the debate, things started out like normal with Cruz and Lee teaming up against the world. Together, the pair were pushing the Consumer Protection Option, an amendment to the Senate healthcare bill allowing insurance companies to sell plans that don't comply with Obamacare regulations.

And then the Texas Republican decided to cut a deal with leadership, to water down the Cruz-Lee amendment, and to support the healthcare law as written. Lee, traditionally his closest ally, was caught off guard by the move.

"Cruz pitched [the updated amendment] to him Wednesday night," said Lee spokesman Conn Carroll, "but it was news to us Thursday that it was going to be in the bill."

That alarm was evident in Lee's decision to immediately and publicly put on the proverbial brakes. "Just FYI – The Cruz-Lee Amendment has not been added to BCRA," he tweeted Thursday morning. "Something based on it has, but I have not seen it or agreed to it."

Translated from parliamentary parlance, that mundane wait-and-see statement could mean major trouble for Majority Leader Mitch McConnell's slim hopes for healthcare reform. But a source familiar with the partnership and subsequent negotiations between the senators said there was no reason for Lee to be surprised.

Though declining "to get in a back-and-forth about member conversations," the source told the Washington Examiner that on Wednesday night "it became clear that the Consumer Protection Option, as originally presented was going to be amended. And it was going to be included in the bill the next day."

Regardless of how the updated language found its way into the legislation, Lee still seems more than hesitant. "Communication between the principals has been that Sen. Lee could not support the revised version," Carroll said, describing his boss' current thinking. "At minimum, he needs more time now to review the bill."

Apparently, he's not alone. During a Thursday morning briefing, some Republican staffers thought that both Lee and Cruz had given their input on the updated amendment. One aide complained that there had been no attempt to clarify that the updated provision was just a Cruz initiative.

All of this suggests a significant shift in the Cruz-Lee partnership that's given McConnell fits for the better part of a decade. The last time the duo teamed up to fight Obamacare in 2013, they ended up shutting down the government. After Cruz jumped the gun, the pair now seem to be growing apart.

That could be symptomatic of Cruz 2.0, the senator's post-2016 persona, a persona defined by policy pragmatism rather than political ideology. The fiery conservative has taken a different strategy in the Trump-era, working more often with than against Republican leadership.

Then again, the mix up between Cruz and Lee might not matter. According to a source with knowledge of the legislation, there's a good chance the updated Consumer Protection Option won't make it through the legislative process. One could be excused for wondering the same about the conservative duo.

Philip Wegmann is a commentary writer for the Washington Examiner.