Former House Speaker Newt Gingrich is sliding downward from the polling heights to which he had soared to just 10 days ago. And a look inside the reasons for his slippage suggest he may struggle to reclaim momentum in advance of the Jan. 3 Iowa caucuses.

U.S. Republican presidential candidate and former U.S. House Speaker Newt Gingrich (L) and his wife Callista talk to customers at the Hy-Vee grocery store in Mount Pleasant, Iowa, December 20, 2011. REUTERS/Jeff Haynes

* Ad Blitz(ed): When Gingrich’s campaign imploded in the early summer, one of the major knocks against him/it was that he was unwilling to do the sort of nose-to-the-grindstone fundraising necessary to raise the millions it takes to run a multi-state presidential campaign.

Some things just don’t change. While Gingrich’s fundraising has undoubtedly increased since he became the hottest thing in the Republican race roughly a month ago, his ad buys in Iowa — $242,000 on television for this week — suggest that he remains cash poor.

That problem is compounded by the fact that Gingrich’s rivals — Texas Rep. Ron Paul, Texas Gov. Rick Perry and the super PAC supporting former Massachusetts governor Mitt Romney — are far better funded and training all of their ad fire on the former Speaker. Romney’s super PAC — Restore Our Future — has pledged to spend more than $3 million in Iowa over the final month of the campaign, a massive sum that alone could drown out Gingrich’s ads easily.

No candidate can hope to win a race with that sort of spending disparity. Gingrich, or his “Winning the Future” super PAC, have to find a boatload of money for ads — and quick.

* Positive is negative: We’ve written before that Gingrich’s pledge to stay positive — not attack his opponents — is a strategic mistake of major proportions.

While negative ads are derided by politicians and the voters they are courting, the commercials continue to be run for a very simple reason — they work.

Gingrich’s “big idea” ads, which is currently running in Iowa, are nice looking but won’t work to rebut the searing negative commercials being run against him in Iowa.

“You know what makes Barack Obama happy,” asks the narrator in the new “Restore Our Future” ad. “Newt Gingrich’s baggage.” The ad goes on to detail the $1.6 million in payments to Gingrich from Freddie Mac and the fact that he was reprimanded as Speaker among other things.

Like it or not, a negative charge unanswered is (generally) a negative charge believed by voters. And with so much negative information swirling about Gingrich, it’s virtually impossible for him to begin to build a comeback unless he starts fighting back on television with real money behind it.

* Debate-less: Gingrich’s comeback was built on his performances — strident, unapologetic and larded with red meat for conservatives — in debates.

But, the final debate before the Jan. 3 Iowa caucuses was last Thursday night, meaning that paid communication (i.e. TV ads) are now the dominant means of communicating with lots of voters all at once. And, as we have noted above, Gingrich lacks the financial power to do that.

Without debates to push his message, Gingrich will struggle for political oxygen at the most critical time in the campaign.

* Organization-less: The not-so-hidden secret of Gingrich’s Iowa rise is that he lacked even the most basic elements of a political organization. And, while we do believe that organization — as traditionally defined — may matter less and less due to the influence and growth of the Internet and national cable as information distributors, it still matters some.

Organization means surrogates to defend a candidate — both on television and in one-on-one conversations with voters — from negative attacks. It means an ability to organize — there’s that word again — phone banks and other means of pushing back in early states on negative headlines voters might be seeing. While Gingrich is doing everything he can to build an organization on the fly, it’s not there yet. And he needs it to be.

All of the above suggests that if Gingrich has indeed peaked too soon, it may be hard for him to claw back in time for the caucuses.

That said, in a field with so many undecided Iowans it has, and continues to be, difficult to predict where this race is headed.