Last week John McCain came alive. He’s a mercurial fellow – sometimes obviously bored, more often careening around his surroundings like a white, scarred and bowed Tasmanian devil, occasionally bursting with temper, often joking, very occasionally mild and funny. But he really comes to life when a conflict is around and he knows who the enemy is. The enemy can be the president of Russia or fellow Republican senators, but they’ll know it if McCain is on the warpath.

Not many senators, after all, knew who Mikhail Saakashvili was before last weekend. McCain did. He’d spoken to him often, even nominated him for a Nobel peace prize in 2005. Randy Scheunemann, one of McCain’s closest neoconservative advisers, was paid by the Georgian government to lobby for it in Washington. And McCain’s long-standing hatred of the Russian government is common knowledge. He once mocked George W Bush for his eminently mockable statement that he had looked into Vladimir Putin’s eyes and seen a force for good. McCain said he’d looked into Putin’s eyes and seen three letters: K, G and B.

So Putin’s invasion of Georgia brought out the fiery righteousness that has marked the McCain family for generations. He dominated the news, eclipsing the laconic Barack Obama, holidaying in Hawaii, and the hapless American president, still making faces in the crowds at the Olympics. McCain sent a delegation, held press conferences, issued vague threats and championed the plucky Georgians. The prospect of another armed conflict – even better against the old Russian enemy – seemed to lift his mood. And it may lift his ratings.

Nobody who knows McCain was surprised. His ancestors, as Matt Welch pointed out in the best short biography of the man, The Myth of a Maverick, have served in almost every war America has been involved with since the war of independence. McCain’s ideal president is Teddy Roosevelt and if you want to understand McCain’s view of the world, a quick perusal of Roosevelt’s presidency is about as good a primer as you can find.

“For the McCains of the United States navy,” McCain wrote in his 2002 book Worth the Fighting For, “as well as for many of our brother officers, presidents just didn’t get much better than Teddy Roosevelt. He transformed the American navy from a small coastal defence force to an instrument for the global projection of power.” Roosevelt was also a pious scourge of the corrupt, a military adventurer who went on to win the Nobel peace prize and a pioneer of environmental protection. He loved finding enemies and defeating them and saw America’s future partly in world adventurism.

McCain’s core belief – after many years of partying, philandering and generally goofing around – is that Americans are at their best when committed to a higher noble cause. And no cause is more noble than projecting American power everywhere on God’s earth to deter evil, reward good and save the victims of bullies. I am not aware of any war in recent times that he hasn’t at some point supported. Peace-time makes him nervous, listless.

He favoured the first Gulf war and the second Iraq war. He wanted to intervene early in the Balkans in the 1990s, favoured the Afghanistan war and wanted more military pressure against North Korea. He also wants to keep the military option against Iraq prominently on the table. His problem with the Iraq war was that the United States did not send enough troops and his support for the “surge” was, to his credit, a defining moment in his recent career.

So a dramatic, polarising conflict with Russia has come as God’s gift to the Republican nominee as he trails Obama by a frustrating few points and seems unable to get ahead. It’s even better that the cause is all but hopeless and that the notion that the West will escalate conflict with Russia to insist on Georgia’s right to South Ossetia is preposterous. The hopeless-ness of this situation is partly what appeals to him.

Vietnam was his template. It was a losing battle but he fought it honourably. The United States lost the war and McCain lost his soul in that Hanoi Hilton, eventually cracking to make false taped confessions under the exact techniques now deployed by Bush against terror suspects. But he survived and refused to be released early and came back home a tortured war hero.

There’s your formula: tragic, noble victim. Domestically his great cause has been preventing lawmakers from bringing pork-barrel spending to their districts – a practice that is as old as all representative government – and curtailing campaign spending in a country where there is a First Amendment that will never, mercifully, be repealed. Yet McCain is still drawn to battling for the impossible. It somehow gives him meaning and purpose.

He is drawn to the beleaguered Kurds, the victims of genocide in Darfur, the people of Burma, the massacred Bosnians and now the plundered Georgians.

Watch his rigid, impassioned performance last week and you will see the president he would surely be. If he becomes president, there is no knowing what he would do to defend Ukraine or any other country bordering Russia. He will certainly be prepared to go to war to stop Iran going nuclear – and will strongly support Israel if it initiates the conflict.

He will never withdraw all troops from Iraq – because the withdrawal of troops always means surrender to him. He wants a “surge” for Afghanistan. And he has pledged not to raise taxes to pay for any of this. You want a Bush third term? McCain would take us right back to Bush’s first, with bells on.

The question that Americans must decide in November is whether, at this point in history, after the five-year $3 trillion (£1.6 trillion) occupation of Iraq, witha nuclear Iran on the horizon, an oil-fuelled Russia resurgent, with the American economy teetering and the Taliban rebounding in Afghanistan, the right direction for America is more military aggression, more presidential power, more unilateralism and less diplomacy.

What you saw last week is a taste of what may yet be to come. And if it sounds like a doomed strategy, it will only make McCain embrace it even more.

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