Politics can turn exciting - as in Gordon v Tony or David v David - and newspapermen like excitement. But politics can also turn chaotic - and then those who write, just like those who read, should feel only apprehension. So to the plight of George Bush and the one man who can save his presidency.What, Bush in chaos? That seems to be overexcited, to be sure. He has three full years to run and clear majorities in both houses of Congress. He's secure, a leader beyond ousting. Maybe a certain incoherence lets him down, but his administration marches volubly on, unapologetic and seemingly unafraid.Yet look closer. Opinion polls have been getting worse since Iraq turned sour. Bush can command approval ratings of only about 35%, his lowest in five years. What goes down can always go up, you say, and did after Ronald Reagan had fallen far further; but Reagan saw big things - like goodbye to the cold war - go right; and the spirit of Gorbachev doesn't stalk downtown Baghdad.Worse, there are some perceptions that can't be swept away by strokes of good fortune. Is Bush "honest and ethical" ask the polls, and 68% of Americans answer no. Is he a winner or a loser when real votes have to be cast? Last week's Virginia gubernatorial defeat is pressing all manner of panic buttons.Bush, in sum, has lost his way. He needs Iraq to work out wonderfully and pretty damn quick. He needs to revolutionise verdicts on his New Orleans performance, not to mention his supreme court nomination shambles. And he needs, quite desperately, to become relevant to his own party again.You can't govern for very long, no matter how big your majority, if your party raises a bleak two fingers and crosses the street when it sees you coming. (The Anthony Lynton Blair memorial lecture on a far grander stage.) But that's exactly today's Republican affliction: no consensus on budget deficit cuts, only unhappiness and a pork barrel wheeled irresolutely around in the wings. The splits between "moderate" Republicans in vulnerable constituencies and rightwingers who preach without fear of retribution are opening wide.And so to the fatal flaw that has dogged this second term from day one, the simple question with no available answer: after George, who or what? If presidents don't make a stab at answering that question when they choose a vice-president - a Gore, a Papa Bush, a Mondale or even a Nixon - then their inheritance crumbles to instant dust. They have no legacy, because their political span stops vacantly short.That was the choice Bush made when he picked Dick Cheney for another term. It's the decision that, day by day, brings him down. If you haven't got a designated heir and an administration that sees the chance of continuing life in transferred allegiances, then you've only got time, running out. Cheney is not a candidate. He is too old, too sick and in too much trouble. The prosecutors who pursue his chief of staff pursue him too. The White House's lousiest moral maze wanders straight up Pennsylvania Avenue to his door.This situation upends the first-term dynamics when Cheney was the experienced professional and chum of dad who exercised more influence than any vice-president in memory. Without him, Saddam would still be in charge of Iraq, looking for his own WMD. Without him, Colin Powell would still have been the voice of American foreign policy.But now Cheney is shaky and absolutely no mover. Every time he climbs into some bully pulpit and snarls defiance, Bush's ratings slide again. The party looks out three years and sees contenders circling. Condoleezza Rice has said she'd never stand, which leaves John McCain, a favourite again at 67; Rudy Giuliani, if memories for 9/11 last; George Pataki, from Albany - and many more. The current party of government is future-obsessed. The Oval Office it holds is a pear-shaped irrelevance.Is that good news for the world's next three years? No more than that a scramble of Campaign groupers and disaffected ex-ministers can hold our parliament to ransom. Odd though it may seem to say it, Bush - in office but not power - will need to recover at least some authority. Goodbye dear Dick, your time is up. Resignation offered and accepted. Hello to a successor with 2008 traction - say Senator George Allen, from Virginia. If you can't go on in some shape or form, then you can't go anywhere. And that's not excitement: it's creeping chaos.