London, England (CNN) -- Elections, the American commentator H.L. Mencken once insisted, are the process in which all the parties rush around the country insisting that the others are unfit to govern, and in the end they are all proved right.

Certainly the tone of the second TV debate between the leaders of the three main parties was a great deal sharper. When Gordon Brown joked, with the aid of his speaking notes, that hearing Messrs Clegg and Cameron in dispute reminded him of his two young sons squabbling at bath time, Nick Clegg retorted sharply that Brown's joke had probably been better delivered in rehearsal.

"Get Real, Nick" said Gordon Brown and he and David Cameron ganged up in trying to depict Clegg as irresponsible over his willingness to put the future of Britain's Trident nuclear weapons system into the defense review they all agree should be conducted.

Fortunately for Clegg their attack was rendered less harmful by the bunch of former military chiefs who wrote to the London Times making the same demand as Clegg and suggesting there might be better ways of spending the money to curb terrorism or equip our troops.

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Clegg and Brown ganged up in trying to depict Cameron as a rigid ideologue who would prejudice Britain's interests in fighting crime and terrorism because of his eagerness to pick a fight with Europe and repatriate powers from Brussels.

Clegg and Cameron were together in insisting that the government had sent troops to Afghanistan improperly equipped.

But for all the point scoring the debate was a huge success. All three have raised their game and I doubt whether so many British voters have ever heard so much policy detail at one sitting. And with only one more to go Clegg has demonstrated that he is not a one-debate wonder but likely to last the course.

Brown was the biggest improver in round two and his opening statement made his purpose clear. If it is all about style and PR, he said, then forget it. But remember that, whatever you think of me, I can deliver. He closed by insisting "the buck stops here" and be declaring that Cameron was a risk to economic recovery, Clegg a risk to the nation's security.

Brown, sensibly, is playing the experience card and playing it quite well. Like the others he knows that after the end of a parliament which had become a by-word for corruption, with all those stories about politicians' expenses fiddles, the public wants change. But as the leader of a party which has been in power since 1997 he knows he cannot convince as the agent of change. He is stuck with offering security and stability.

The key for Brown now is not to let the gap between his third place and the Lib Dem and Conservative poll ratings grow too far, because, such are the vagaries of the British voting system, that he could come third in terms of vote share and yet still have more Parliamentary seats than the other two parties.
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* British Politics
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* Nicholas Clegg
* Gordon Brown
* David Cameron

David Cameron's problem is that he had set out to be the agent of change, hence the greening and modernizing of the Conservative Party. It was the trick pulled off by Tony Blair before he led Labour to victory in 1997: "I have reformed and refashioned my party, now I am ready to do the same for the country."

But despite leading in the opinion polls since the end of 2007, Cameron has somehow failed to seal the deal with the public. Even a fair number of Conservative don't feel quite comfortable with him and his financial chief George Osborne.

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Cameron too was sharper in Round Two, more confident and persuasive. One bookmaker rather curiously paid out on him as the "winner" of the debate. Tricky to be sure of that when there is no finishing line. But Cameron has also begun to sound more like Margaret Thatcher than he has ever done -- the Euro-skepticism, the insistence on careful spending, the use of Conservative code words like "school discipline."

It all sounded like an attempt to reassure the core Conservative vote. But the more he does that the greater his risk with those crucial floating voters.

The game has changed for Cameron. Clegg's seizing of his opportunity in the first TV debate has established him as the agent of change. For Cameron to secure a working majority he now has just a fortnight to knock out or at least to marginalize Clegg.

The Conservative leader's allies in the media are certainly doing their best to help him. Some of the attacks on Clegg in the press have been fair game -- politics in Britain is a robust sport -- others have varied between the laughable and the vile.

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So over-the-top have some of the attacks on Clegg been that Twitterers started a fanciful collection of the other sins that could be laid at the Lib Dem leader's door. He had been seen poking a stick into Iceland's Eyjafjallajokull volcano, his was the face seen on the grassy knoll as the JFK entourage swept by and it was Clegg who sabotaged the pitch to ensure that David Beckham snapped his Achilles tendon in the World Cup run-up.

Labour has been muddled in its attitude to a hung parliament, in which no party can claim a ruling majority and coalitions must be formed.

Home Secretary Alan Johnson has beamed his acceptance of the idea, Gordon Brown's long-time ally Ed Balls has insisted that it is not the British way of doing things. The Conservatives, however, have been adamant that a hung parliament represents a massive danger.
If no party has a governing majority, says Cameron, and his is the only party which retains the hope of one, then we risk a falling pound, higher interest rates and a dip in Britain's credit rating. Former finance minister Ken Clarke warns that in a hung parliament the IMF might have to bail Britain out.

Good tactics? Or could that too be a tactical error? Will the public really take kindly to the Conservatives saying "Vote for us or take the consequences?" His worry must be that that could prove just another reason for young voters at least saying:"We'll give that guy Clegg a try?"