A spokesman for Sen. John McCainJohn Sidney McCainLawmakers worry about rise of fake video technology Democrats put Dreamers and their party in danger by playing hardball Trump set a good defense budget, but here is how to make it better MORE (R-Ariz.) is criticizing Sen. Ron JohnsonRonald (Ron) Harold JohnsonTrump spars with GOP lawmakers on steel tariffs Overnight Regulation: Trump unveils budget | Sharp cuts proposed for EPA, HHS | Trump aims to speed environmental reviews | Officials propose repealing most of methane leak rule Trump budget seeks savings through ObamaCare repeal MORE's (R-Wis.) remarks suggesting McCain's brain cancer might have been a factor in his vote against ObamaCare repeal.

"It is bizarre and deeply unfortunate that Sen. Johnson would question the judgement of a colleague and friend," a McCain spokesman told NBC.

"Senator McCain has been very open and clear about the reasons for his vote," said the spokesman, who was not identified by name in the NBC report.

McCain was one of three Republican senators to buck their party in voting against the Senate GOP's scaled-down ObamaCare repeal bill.

Johnson earlier on Wednesday told a Chicago radio station that the late hour of the vote and McCain's tumor might have "factored in" to his decision.

“He has a brain tumor right now, that vote occurred at 1:30 in the morning. Some of that might have factored in,” Johnson said.