(CNN) - They're at it again.
Rand Paul was asked in a recent interview to name one word when he thinks of fellow Republican Chris Christie.
"Bridges?" he said with a knowing grin during a sit-down with KET's Bill Goodman.
The Kentucky senator’s dig marks the latest round in the back-and-forth between the two potential presidential contenders - a feud started last year in a war of words about surveillance and government spending.
Christie’s administration has been rocked by scandal over suggestions top appointees orchestrated the closure of access lanes to the George Washington Bridge last year – causing big traffic tie ups - as political payback for a local mayor who did not back the governor’s reelection.
A state legislative committee is spearheading an investigation, while federal prosecutors are also reviewing the matter.
Although there is no evidence that Christie was involved, the scrutiny and the resulting controversy continues to dog him. It has also raised questions about his leadership and forceful governing style that has been popular with New Jersey voters.
Paul was also asked to briefly describe other potential White House rivals, including Texas Gov. Rick Perry, another conservative with whom Paul has recently sparred.
"It's hard to put it in one word," Paul said. "I like the fact that he has been for more power for states and for less government in his state. We have some disagreements on some other things.
Hillary Clinton? "Yesterday's news," he said.
Barack Obama? "Affable but often ineffectual."
Marco Rubio? "Thoughtful and part of the answer to making our party bigger - a good, new face for our party."