After years of strained cordiality in the Kentucky Senate delegation, Sen. Mitch McConnell (R) has forged an unlikely but good rapport with Sen. Rand Paul (R).

At the time that Sen. Jim Bunning (R) retired, he and McConnell hardly spoke, and it looked like Paul might fare no better. The blistering Republican primary for Senate last year saw Paul topple Kentucky Secretary of State Trey Grayson, whom McConnell feverishly worked to elect.

But so far, the bitterness of that contest seems not to have spread to Washington, D.C.

In fact, McConnell has taken to praising Paul’s brand of conservatism in public speeches, most recently in a speech at the Jefferson County Republican Party Lincoln Day Dinner in Louisville, where Paul introduced the Minority Leader as the keynote speaker.

McConnell also singled out Paul in his speech last week to the Conservative Political Action Conference, calling him one of the “great freshman conservatives … already taking strong, principled stands in the Senate.”

The senior Senator from Kentucky did not always speak so kindly of Paul’s views.

During the primary, McConnell actively discouraged Republican colleagues from supporting Paul, who had strong backing from the grass-roots tea party movement. Paul, in turn, hinted that McConnell might not be his choice for leader if he won the seat.

Paul’s victory over Grayson was an embarrassing defeat for McConnell and the Republican establishment, but several sources close to both Bluegrass State lawmakers said they mended fences quickly after the primary.

“A week after the primary, Sen. McConnell held a unity rally and no one looked back,” Paul spokeswoman Moira Bagley said. “The most important task was to elect a Republican Senator from Kentucky. Fortunately, through that, the Senators, and staff, established a strong relationship.”

Paul told Roll Call that the first phone call he made after he won the primary was to McConnell.

“That made some of our people mad who, you know, had disagreements because he didn’t support me,” Paul said. “But in the end he was very gracious; he helped me, traveled on the campaign bus.”

Trygve Olson, a Republican strategist who served as the field consultant between the Paul campaign and the National Republican Senatorial Committee, described one occasion during the campaign when McConnell changed his schedule in order to attend a tea party rally with Paul.

As the bus drove to the rally, McConnell peppered Paul with questions about his tea party supporters, what they wanted politically and how they were drawn to the movement.

“McConnell was fascinated with the idea of connecting with people who had never been involved in politics,” Olson said.

He said McConnell understood that Paul represented a constituency of people who are critical for the senior Senator from Kentucky to understand, while Paul had deep respect for McConnell’s knowledge of politics.

As the campaign went on, their relationship — and those of their staffs — continued to evolve so that by the time Paul’s first debate on Fox News occurred in October, senior members of McConnell’s staff played critical roles in Paul’s debate prep.

But it has been a quiet opening for the Senate, with few significant votes and nothing that might split McConnell’s establishment instincts from Paul’s assertively populist conservativism. Republican aides said McConnell and Paul’s relationship has yet to be tested.

“The real test will be in the coming months and years as Rand Paul continues to hold the conservative line when leadership tries to center the caucus,” one Senate GOP aide said. “Those two roles are in tension and conflict — I don’t see Rand Paul changing and I don’t see Mitch McConnell changing.”

However, aides close to the two lawmakers said the increased communication between their respective staff could help diffuse potential conflicts.

Paul confirmed the two lawmakers speak “almost every day” and readily admitted he had much to learn about how the Senate operates.

“I’m really concerned with what we just have to do as far as cutting spending and really have not been here long enough to understand and be a part of how you actually make it happen, other than for me to try to be loud and vocal about how we do what we need to do as a country,” Paul told Roll Call.

Olson noted their relationship has been built on a mutual appreciation for what the other has achieved.

“Mitch McConnell is extraordinarily smart about politics,” Olson said. “In Rand’s case, McConnell became a key mentor and confidant on the art of the political.”

One Republican aide with close ties to Kentucky said McConnell’s acceptance of Paul is a prime example of the Minority Leader’s political aptitude.

“McConnell is a very shrewd politician,” the aide said. “He doesn’t need his right causing him trouble at home.”