With Newt Gingrich the clear and undeniable frontrunner in the GOP Presidential primary a lot of artillery fire is now being directed his way. While Mitt Romney's campaign has rolled out its surrogates to blast Gingrich, it is not that 2008 contender that Gingrich should worry most about. Instead, it's another unlikely duo of 2008 contenders that could end up doing the most damage.

First and foremost among Gingrich's enemies is Ron Paul. The Texas Congressman has blistered Gingrich both on TV and in debates. His ads are vicious, yet probably effective. The latest hit is a one-minute spot that calls Gingrich a "serial hypocrite" and hammers him for taking money from Freddie Mac before the housing bubble burst. Paul has also made much hay over Gingrich's policy reversals over the years.

Troublesome for Gingrich is the fact that Paul is a much more effective messenger. For decades Paul has been an unflappable and unbending conservative in Congress, never wavering to the establishment's whims. If anyone has the grativas to hit someone for flip flops in the 2012 field, it's Paul.

Paul is also a clear and present danger to Gingrich politically. A Public Policy Polling (PPP) survey out today has Gingrich and Paul virtually tied in Iowa, with Gingrich at 22 to Paul's 21. If polls were showing the same thing on Caucus night, Paul would likely cruise to victory as he has a far stronger and more robust field operation than Gingrich, who has only recently dug his campaign out of debt and lacks much of a campaign infrastructure. 

The Washington Post's Chris Cilizza has dubbed Ron Paul "Mitt Romney's Best (Iowa) Friend." Paul could nearly single-handedly crush Gingrich's candidacy by weakening the frontrunner with a loss in Iowa. 

A second threat to Gingrich, who also ran in 2008, looms in Colorado's own illegal immigration firebrand, Tom Tancredo. 

Tancredo has already proved himself adept at taking down frontrunners not named Mitt Romney. Before Rick Perry even entered the race, Tancredo penned a column in Politico hitting Perry hard on his stance on immigration. A narrative set up by Tancredo was further flushed out when Perry made the mistake of saying those that oppose his plan for allowing in-state tuition for the children of illegal immigrants "don't have a heart."

Tancredo told Caplis and Silverman (630 KHOW) in October that he "hope[d] he helped kick some holes in [Perry's] boat."

Now that Perry is no longer the frontrunner, Tancredo has flashed his rhetorical daggers again, this time taking it to Newt Gingrich over illegal immigration in another Politico piece entitled "Can GOP accept Newt's immigration policy?"

In the piece, Tancredo rips Gingrich apart for his past support for amnesty legislation and suggests that Gingrich's immigration policy will be his undoing in the primary. 

It is an interesting turn of events. Two candidates that ultimately amounted to also-rans in 2008 have become some of the most influential this time around. 

If Gingrich is able to weather the attacks of Tancredo and the charging force of Ron Paul in Iowa, he will be well on his way to the nomination. But first he has to get past them.