The Times Square bomber was barely in custody before Skippy McCain, John's evil twin, appeared on the talk shows to vent his studied fury. How dare the suspect be read a Miranda warning! Skippy was certain this soft-headed, non-24 response would stop Faisal Shahzad from talking.

Never mind.

Under a national security exception invoked in the midst of a continuing threat, it turns out that Shahzad didn't hear his Miranda rights until he had already spilled what the FBI described as "valuable intelligence"—and he kept the flow going after he was Mirandized.

Even Glenn Beck thought Shahzad, an American citizen, ought to be accorded his constitutional rights: "We don't shred the Constitution when popular,” he said. “We do the right thing." But facing a primary challenge from the nether regions of the far Right, Skippy McCain shredded away. In the theater of the absurd that is Tea Party politics, the  proverbial maverick  has shape-shifted into a pandering mouthpiece for the Right, grumpily lurching across the public stage. Read his lips: There's hardly a past conviction he won't renounce as he desperately trolls for votes.

In January, when the Senate roll was called on the deficit reduction commission that McCain had co-sponsored, he voted against it—out of fear of the conservative magisterium of the unelected anti-tax zealot Grover Norquist. But McCain’s denunciation of a bill he had co-sponsored was just one sad scene in a long-running spectacle now well into its second year.

In opposing the Obama economic recovery plan, McCain proposed an alternative that consisted primarily of tax cuts for the wealthy—the very policy the maverick had said he could not "in good conscience" support under George W. Bush in 2001, before Bush’s avalanche of tax cuts had buried the country in debt.

McCain turned his mouth seven years later, during his pursuit of the Republican presidential nomination, promising to make the Bush tax giveaways permanent. Some observers excused his hypocrisy, viewing it less as a betrayal of his beliefs than as an inevitable accommodation to a GOP base that could barely accommodate itself to the pre-Palin McCain.

After the election, it was widely assumed that the defeated McCain would revert to form—that he might even be the bridge to the bipartisanship prized by the new president. Instead, driven by transparent resentment toward the younger man elected president in his place, McCain not only marched in Republican lockstep during the economic recovery debate, but has surrendered unconditionally to the wing-nut opponent now assaulting McCain's Senate seat. (Remember McCain's "No Surrender" bus tour in 2000?)

Having abandoned rational discussion, let alone leadership, on climate change, McCain now scorns the legislation he once championed as a "monstrosity." His perennial sidekick, South Carolina Sen. Lindsey Graham, pledged to push the bill through alongside John Kerry. But suddenly, for McCain's sake perhaps as much as his own, he's walked away, dooming any realistic chance of passage this year or maybe for many years.

Immigration reform is another initiative McCain authored, then soft-pedaled in the 2008 campaign, and now pretends is a bastard proposal he doesn’t recognize and won’t support. Repeating rote Republican talking points, he speaks only of border security, which he previously dismissed as a fool's mission without comprehensive reform: "We can never build an impenetrable wall to the north and south of us," he said.

Indeed, nowhere has McCain's degradation been more pronounced—or repellant—than on this issue. He rushed to embrace the Arizona racial profiling law, under which local police are supposed to interrogate anyone who looks like an illegal alien. McCain offered the batty rationalization that "the drivers of cars with illegals in it [sic] ... are intentionally causing accidents on the freeways.” His hypocrisy is so flagrant as to be disorienting, giving him the aura of the archetypal uncle lost in the attic of delusion. Yet his inauthenticity is tragically rational, driven by his desperate need to win over a GOP primary base bounded by bigots, birthers, and backwardness.

We used to think McCain was different. Those who disagreed with him—he always was conservative, but never a prisoner of dogma—admired him. His bad temper underscored a cranky realism, and he was open to ideas and progress that transcended party lines. John Kerry, who had worked closely with him in the Senate, believed he could work with him as vice president and asked him to consider joining the ticket in 2004. That ticket would have won. But McCain, with his eye on 2008, rebuffed the overture, and lost his main chance for national office.

He also began to lose something more. The Kerry campaign broadcast an ad comparing the Swift Boat lies about Kerry to the anti-McCain smears peddled by Team Bush in the 2000 South Carolina primary. The spot challenged George Bush to condemn the lies. McCain sent word that if Kerry didn't cease citing Bush’s attack on McCain, McCain would attack Kerry—who'd defended McCain from the smears in 2000. McCain was making it clear that he would rather abet lies than nick his hopes of gaining the Republican mantle in 2008.

As a young pilot, McCain was a brave and defiant POW in Vietnam. Now he cowers before his primary challenger, J.D. Hayworth, a hapless radio host and professional blowhard. My bet is McCain wins his race. The question is at what cost?

In Robert Bolt's play, A Man for All Seasons, Sir Thomas More, Henry VIII's former chancellor, refuses the king's demand that he swear a false oath. More confronts the ambitious Richard Rich, who has perjured himself on the king's behalf and whose testimony will send More to the executioner's block. Rich has been rewarded with the post of attorney general for Wales.

More says to Rich: "Why Richard, it profits a man nothing to give his soul for the whole world. But for Wales?"

Even amid the ethical wreckage of his 2010 campaign, McCain must know that the whole world is well beyond his tarnished reach. But for a seat in the Senate?