You wouldn’t expect much interest beyond the United States, or even beyond his own state, when an 80-year-old conservative legislator, who has already served six terms, loses his party’s endorsement to run yet again. But the crushing defeat of Senator Richard Lugar in the recent Indiana Republican primary, in a Tea Party-supported campaign of shocking mindlessness, has reverberated in capitals around the world, including my own.

On most issues, Lugar is and always has been a natural conservative. In recent times, he opposed all of President Barack Obama’s major domestic legislation, including the economic stimulus package, health care reform, and financial-services regulation, and has consistently supported anti-abortion legislation. With his 36-year record in the U.S. Senate, national stature, and essentially conservative constituency, he would certainly have won again in November. But none of this was persuasive enough for Indiana primary voters, who backed his rival, State Treasurer Richard Mourdock, by an astonishing 20-point margin.

The problem for Lugar was twofold. First, he was of the old school that instinctively embraced compromise across party lines in the Senate on crucial issues, in order to avoid the kind of gridlock that is always potentially endemic in a presidential system (unlike a parliamentary one), where the elected executive has no guaranteed majority in the legislature. If party lines are strictly maintained, U.S. presidents may be unable to pass any legislation at all, or to make any judicial or other senior appointments.

Lugar, for example, had voted to confirm Obama’s Supreme Court nominations. Mourdock’s position, by contrast, was that, “Bipartisanship ought to consist of Democrats coming to the Republican point of view.”

Second, and most alarmingly for those around the world who crave decent and intelligent international leadership from the U.S., Lugar was mocked by his opponents for his foreign-policy expertise and reputation as an outstanding statesman. For decades, he had played an absolutely central role on arms control and disarmament issues. His signature achievement was joint authorship with then-Democratic Senator Sam Nunn of the 1992 Cooperative Threat Reduction program (universally known as “Nunn-Lugar”), which successfully secured and dismantled nuclear and other weapons of mass destruction in former Soviet states.

Beyond that, Lugar had fully supported Obama’s vision, like that of President Ronald Reagan before him, of a world without nuclear weapons. His endorsement of the New START treaty with Russia, reducing the number of deployed strategic weapons, was crucial in securing its narrow ratification by the Senate last year. But, for Mourdock and his supporters, “The time for being collegial is past – it’s time for confrontation.”

One television advertisement said it all about the low-rent cynicism of the Tea Party-driven campaign. It featured two clips of Obama saying, “I’ve worked with Republican Senator Dick Lugar to pass a law,” and, “What I did was reach out to Senator Dick Lugar.”

The context was not explained, but what Obama said in full was this: “I’ve worked with Republican Senator Dick Lugar to pass a law that will secure and destroy some of the world’s deadliest, unguarded weapons,” and, “What I did was reach out to Senator Dick Lugar, a Republican, to help lock down loose nuclear weapons.”

With the defeat of Lugar, and the simultaneous exit of the last Republican moderates, like Senator Olympia Snowe of Maine, who were prepared to put national interests ahead of partisanship, the Senate is unlikely to produce the 60 votes needed to ratify further U.S.-Russia arms-control treaties, should they be negotiated. Moreover, the Comprehensive Nuclear Test Ban Treaty, which would replace a fragile international moratorium, cannot come into force without U.S. Senate ratification.

At a personal level, I am also afraid that Lugar’s defeat may be the end of an era of enormously attractive and distinctive civility in the way that America’s most senior legislators conducted themselves. As Australia’s foreign minister, and a global NGO head, I met Lugar many times, and, whether or not we agreed on issues, he was always a model of gentle courtesy.

I can’t help but compare that to the occasion, not so long ago, when I accompanied my then co-chair of the International Commission on Nuclear Non-Proliferation and Disarmament, former Japanese Foreign Minister Yoriko Kawaguchi, in a call on Jon Kyl, the most ideologically fierce Senate opponent of Obama-style arms control. On my arrival in his office, a senior Kyl staffer, after consulting the senator, said brusquely: “We only agreed to talk to the Japanese, not you. Would you please leave?”

There was nothing like a perfectly understandable, “Sorry, we misunderstood, and are only prepared now for a bilateral session. Can we see if we can possibly reschedule a joint meeting later?” I suppose that I should be grateful that he said “please.” But it’s the kind of experience that I had never had before in Washington, and I fear that it’s not unique.

In the past, anguish at home and abroad about the quality of U.S. governance – its apparent arrogance, mindless parochialism and incapacity to deliver coherent, credible and decent policy outcomes – has for the most part proved short-lived. Maybe that will be the case again. But the passing from the national stage of Richard Lugar has properly rung new alarm bells not only among concerned Americans, but also among policymakers far removed from the U.S. and its partisan battles.

Gareth Evans, a former Australian foreign minister and past president of the International Crisis Group, is convener of the Asia Pacific Leadership Network on Nuclear Non-Proliferation and Disarmament, and chancellor of the Australian National University. THE DAILY STAR publishes this commentary in collaboration with Project Syndicate © (www.project-syndicate.org).