The silly season is upon us. With Hillary Clinton's cleavage and Judith Giuliani's expensive handbag passing for big news, the presidential campaign, or at least the media's attention span, has been defined down.

Voters are probably distracted, but they shouldn't be fooled. Behind the garbage hunt and the trivial pursuits, something big and important is happening.

The horse races for the nominations are settling into a pattern that could last all the way to the finish line. After seven months of false hopes and starts, we're essentially back to where we were at the beginning. Hillary Clinton is firmly atop the Democratic pack, and Rudy Giuliani has weathered a slump to grab the GOP lead.

In a sampling of national polls Friday, realclearpolitics.com had Clinton up by an average of 16 points over Barack Obama, while Giuliani had stretched his average lead to 9 points over Fred Thompson.

Coming after debates and forums and months of rubber-chicken and baby-kissing, the shakeout is starting to feel like the real thing. Clinton and Giuliani always have been the most likely to come out on top, and it's a big deal for them to be where they are at this stage. With the first votes in January, it's no longer early.

You better believe their challengers see it that way. Their actions — their desperate actions — are giveaways. Panic took hold in a number of camps last week as the contenders sensed their chances slipping away. Even if you didn't know what the polls said, you could tell by the mistakes — the cheap tricks and flip-flops on issues the contenders once touted as matters of principle — that they were Nervous Nellies.

But panic, as it usually does, only digs you a deeper hole. And that's exactly where three challengers ended the week.

Obama was the big loser. Slipping 21 points behind Clinton in one poll, he suddenly seemed lost when he was caught thinking out loud about nukes over Pakistan. It was more than a rookie mistake. It was as close as the charismatic Illinois senator has come all year to a disqualifying moment, and Clinton was quick to pounce. In full snarky mode, she said, "Presidents should be very careful at all times in discussing the use or nonuse of nuclear weapons." Take that, kid.

John Edwards, deservedly slipping from a serious contender to a distant third behind Clinton and Obama, got caught in a trap of his own making. Proving again he'll say anything to get attention, he demanded Clinton give back a few thousand dollars in contributions from Rupert Murdoch's Fox empire. The ploy was designed to stir up the far-left base, which hates Murdoch, but it backfired when it was revealed that Edwards took $800,000 from a Murdoch publishing house in a book deal on poverty.

Whatever else he accomplishes in the campaign, Edwards has proved that poverty pays. In addition to the book loot, he collected tens of thousands for speeches on poverty and earned more than $400,000 in a hedge fund, where he said he wanted to learn more about the markets and poverty. Throw in his penchant for $400 haircuts and it's amazing that anyone in the country still thinks Edwards should be president.

Arizona Republican Sen. John McCain is also flirting with a flameout. After being one of the most ardent supporters of the flawed immigration bill that died in Congress, McCain suddenly signed on to a new bill that is in many ways the polar opposite. The liberals who loved him in May are now spitting his name, while his conversion to enforcement hawk won't fly with those who demand secure borders.

McCain, saddled with an unpopular position on Iraq, is falling further behind in the money race.

As for Clinton and Giuliani, neither is in a position to coast. Even as they lead in the national polls, state races are tighter in some cases. But their leads mean they won't have trouble raising money and they don't have as much pressure on them in all the early states. The nominations are theirs to win or lose. And once again, it looks as though one of them will be the next president. Sounds right to me.

Michael Goodwin is a columnist for the New York Daily News, Reach him at Mgoodwin@nydailynews.com.