The Senate whips are playing augmented roles on high-profile issues as the relationship between Senate leaders Harry Reid (D-Nev.) and Mitch McConnell (R-Ky.) has become more strained.

As their parties’ respective whips, Sen. Dick Durbin, an Illinois Democrat, and Sen. Jon Kyl, an Arizona Republican, are helping hash out the path and process of the energy bill when it starts grinding through the Senate this week. Durbin was tapped by Majority Leader Reid, while Kyl is working along with Minority Leader McConnell.

But Reid and McConnell have had frosty relations in recent months, most notably evidenced by a particularly sharp exchange on the Senate floor after the June 26 vote on the Medicare bill that is now law. The passage of the Medicare measure was a huge political victory for Democrats and a blow to Senate Republican leaders.

Durbin and Kyl first struck up a working relationship while on the Judiciary Committee. Last week, it was their work that helped break an impasse over amendments to the President’s Emergency Plan for AIDS Relief (PEPFAR) legislation. The bill ended up sailing through the chamber on an 80-16 vote.

They started talking on the energy debate last Tuesday. Durbin and Democrats want to crack down on speculation in the oil futures market before considering other solutions to high gas prices; Kyl and Republicans are insisting on a “balanced approach” that includes allowing oil companies more drilling rights.

Durbin was tapped directly by Reid to discuss amendments and floor process for the bill.

“I’ve directed Sen. Durbin,” Reid said on Thursday. “He’s been working the last 24 hours with Sen. Kyl, his counterpart, to come up with a way to move forward on this legislation.”

Durbin said he volunteered for the job.

“I asked Harry if I could try to see if we could come to an agreement,” Durbin said. “Jon and I worked on PEPFAR and we’re going to try to work on [energy].”

“It’s not unusual,” Kyl said of the talks. “We’re the two whips.”

“They’re a logical pair to be doing what they’re doing,” Sen. Byron Dorgan (D-N.D.), a primary co-sponsor of the Democrats’ energy bill, said of the Durbin-Kyl talks.

The relationship between Durbin and Kyl is central to the operation of the Senate. Not only are the two men their respective party whips, they could potentially be future majority/minority leaders.

Meanwhile, McConnell and Kyl have been dealing with members of the GOP conference who have blocked bills they wanted to pass. Sen. John Ensign of Nevada briefly blocked a housing package in June, and Sen. Jim DeMint of South Carolina last week tried to block the PEPFAR legislation that Kyl was negotiating with Durbin. Sen. Tom Coburn (Okla.) routinely places holds on legislation.

McConnell’s and Reid’s spokesmen emphasized that their bosses are still in command and working effectively with each other.

“They talk all the time,” said Reid spokesman Jim Manley. “Nothing ultimately gets done without the say-so of Sens. Reid and McConnell.”

Durbin himself is also careful to avoid any implication that his relationship with Kyl is better than that of Reid and McConnell.

“I wouldn’t say that — we haven’t done anything yet,” he said. “Let’s wait and see.”

McConnell spokesman Don Stewart emphasized that his boss has not delegated any leadership on the issue, and remains “fully engaged.”

“What’s happened on the Democratic side is not being mirrored on the Republican side,” Stewart said. “Sen. McConnell, as is always the case, leads floor considerations. Sen. Kyl, as always, assists in those efforts.”

Delegating has long been part of Reid’s style. The Nevada Democrat frequently defers to his committee chairmen, most recently when he largely left talks on the housing bill to Banking Committee Chairman Chris Dodd (D-Conn.).

“This is true to form for him,” one aide said of Reid.

There is still the possibility of tension between Durbin and Kyl. Hours after Durbin spoke freely to reporters last Thursday about his talks with Kyl, the Arizona Republican was tight-lipped when asked to respond.

“I’m not going to discuss anything that Dick and I have talked about,” Kyl said. “Sen. Durbin may want to talk about our conversations; I consider them private until something gets resolved.”

Manu Raju contributed to this article.