Longtime ‎political observer Al Cross in Kentucky evoked financial meltdown language to describe this moment in the relationship of his home-state senators.

“I guess Tim Geithner would say it’s a stress test,” said Cross, director of the Institute for Rural Journalism and Community Issues at the University of Kentucky in Lexington, referring to the former Treasury secretary’s measure of banks’ ability to survive a crisis.

“These guys are not cut from the same cloth, but they have a symbiotic relationship,” he said. “Any political relationship only goes so far, and we have seen the limits.”

Advisors and those who know the senators downplayed the trouble in their union, saying both men have long realized that ideological differences would not prevent them from being productive partners in the business of politics.