Dick Lugar's long tenure in the Senate will soon end, and John Kerry isn't happy about it.

Indiana Sen. Dick Lugar, among the longest-serving Republicans in U.S. Senate history, on Tuesday lost his reelection primary to tea-party-backed state Treasurer Richard Mourdock. With Lugar's exit in January, the Senate will lose one of its few remaining members with a habit of working across the aisle.

Sen. Kerry, D-Mass., has worked with Lugar on the Senate Foreign Relations Committee, currently as its Democratic chairman while Lugar served as its ranking member. Lugar is a well-established Republican voice on foreign policy, having coauthored the seminal Nunn-Lugar nuclear nonproliferation legislation.

Kerry lamented Lugar's defeat in a lengthy statement released to press Tuesday night.

This is a tragedy for the Senate and the loss is particularly felt by all of us who have been privileged to serve with Dick on the Foreign Relations Committee," Kerry said. "It's a blow to the institution during a period when the institution itself has been strained. Whether he was serving as Chairman or Ranking Member of our Committee, wielding the gavel or working the floor, Dick's approach to governing was always the same:  he wanted to find serious answers to some of foreign policy's most vexing questions. He's a class act and a gentleman and in a Senate that has seen so much change and transition these last years, his expertise on complicated issues honed over 36 years simply can't be replicated. …

Dick's Nunn-Lugar efforts have become almost shorthand for bi-partisanship in foreign policy, and they should be recognized. But for me, on a personal level, two other efforts stand out as epitomizing who Dick is and why he'll be missed. For me, it started with the work we did together in the 1980's to help bring about free and fair elections in the Philippines. …

It will soon almost sound cliched to say that America is safer today because of Dick Lugar's 36 years of service in the Senate, but it really does bear repeating. His record on our Committee will long be remembered in the same context as another chairman, William Fulbright of Arkansas, whose Senate service also ended in a difficult primary defeat, but who is remembered today not for one loss, but for a legacy of following the facts and speaking the truth despite the political risks. This is a tough period in American politics, but I'd like to think that we'll again see a United States Senate where Dick Lugar's brand of thoughtful, mature, and bi-partisan work is respected and rewarded. That kind of seriousness of purpose should never go out of fashion.