Former Hewlett-Packard CEO Carly Fiorina defended her fiscal plan, known as zero-based budgeting, during the "undercard" Republican debate Thursday night, saying her detractors know it would abolish budget items that are worthless but favored by those who get them. Her budget promise, which has been criticized for its complexity and heavy time commitment, would implement a system that examines every expenditure in the budget and builds up from zero to determine the appropriate amount each year.

“Politicians don’t want to talk about” my plan, Fiorina said during the Fox News/Google debate in Des Moines, Iowa. “In fact, nobody wants to vote on a tax code of zero-based budgeting, because if you do you’re goring everybody’s ox.”

Fiorina was joined onstage by former Pennsylvania Sen. Rick Santorum, former Arkansas Gov. Mike Huckabee and former Virginia Gov. Jim Gilmore.

Zero-based budgeting differs from the current budget approach, known as “incremental budgeting,” which allocates funds based on past need instead of predicted future need. That process itself has been criticized for promoting a “use-it-or-lose-it” mentality where government agencies spend more money than they actually need to maintain funding levels year after year.

Fiorina isn’t the first politician to bring this issue to the national stage. President Jimmy Carter implemented the system when he was president in the late ‘70s. It was abandoned later by President Ronald Reagan.

The path ahead for all the candidates is a steep one that will likely need more than just a tax plan, however. Fiorina has suffered a steep fall in the polls since September, when she surged after a strong debate performance. She has tanked to 2 percent of the vote in national polls, down from a high of 11.8. In Iowa she’s dropped from a high of 10.3 percent of the vote to 1.6 percent.

And, while Santorum and Huckabee are the two most recent Republican winners of the Iowa caucuses, they’ve struggled to make headway in both Iowa and national polls. Huckabee receives 2 percent support in national polls and 2.1 percent in Iowa. Santorum receives less than 1 percent in both contests.

Gilmore doesn’t poll well enough to even register in those polling averages.

Those low-single digit performances are quite the contrast with front-runner Donald Trump. The real estate mogul leads in Iowa with 32.9 percent of the vote and nationally with 35.3 percent, according to recent polls.

Still, those polls in Iowa could be dead wrong, according to Bloomberg. Because of the complicated nature of the Iowa caucus system, screening likely voters can be difficult. As opposed to primary voting, caucusing requires an extended time commitment and generally has much lower turnout. That means that candidates need to motivate their supporters to show up to the caucuses, a challenge that favors those with extensive ground operations.