Carly Fiorina who has not yet offered a tax plan, said she would reduce the tax code, estimated to run some 73,000 pages, to just three. | AP Photo GOP candidates air sharp differences on taxes

The tax plans put forward by Republican presidential candidates rely on some fuzzy math, unrealistic assumptions and gallons of red ink.

That exploded into the open Wednesday as the candidates turned on each other over taxes in their latest debate, straining to poke holes in each others' plans while fending off skeptical questions from debate moderators. At the same time, they often ignored the gaping holes in the budget their own proposals would generate.


The tone was best summed up by Ohio Gov. John Kasich, who blasted his rivals' tax-reform plans as "fantasy tax schemes."

It was the most wide-ranging -- and heated -- debate over taxes by the GOP field so far. Some of the sharpest attacks came from Kasich, who said his colleagues’ proposals would blow huge holes in the government’s budget.

The Tax Foundation has released analyses of tax-reform plans by six of the presidential contenders, and found each would add at least $1 trillion to the debt. Kasich has his own tax-overhaul proposal, though the group says it is not detailed enough for it to analyze.

“These plans would put us trillions and trillions of dollars in debt,” he said. “You don’t just make promises like this – why don’t we just give a chicken in every pot?”

He singled out Ben Carson’s “tithing” proposal, while also appearing to take a shot at Donald Trump’s plan, which is estimated to add $10 trillion to the debt.

“We’re just going to have a 10 percent tithe and that’s how we’re going to fund the government?” or “we’re just going to be great?”

“We cannot elect someone who does not know how to do that job,” said Kasich.

The other candidates fought back with their own facts and figures, saying they would cut enough spending or generate enough economic growth to fend off deficits.

Carson said his plan would create a 15 percent flat tax, not a 10 percent one, despite its association with Biblical tithing, and said he’d pay for it in part with big cuts in federal spending.

"We have 645 federal agencies and sub agencies," Carson said. "Anybody who tells me that we need every penny in every one of those is in a fantasy world. Also, we can stimulate, that's going to be the real growth engine: Stimulate the economy."

Meanwhile, Marco Rubio was questioned over his promises of a family friendly tax-reform plan, when an analysis by the Tax Foundation showed the top 1 percent would see their after-tax incomes go up by almost twice as much as some of those in the middle of the income distribution.

Rubio noted the analysis also showed those at the bottom of the income ladder, in the lowest decile, would see the largest income boosts, according to the analysis.

“The greatest gains percentage-wise for people are going to be at the lower end,” said Rubio.

Ted Cruz touted his own plan, which he laid out in a Wall Street Journal op-ed as the debate got underway. It calls for a 10 percent flat tax on individuals and a 16 percent levy on businesses.

The plan offers “the lowest personal rate any candidate here has,” said Cruz. “What it would also enable us to do is for every citizen to fill out their taxes on a postcard so we can eliminate the IRS.”

The proposal would cost “less than a trillion dollars,” said Cruz, pointing to an as-yet-unreleased Tax Foundation analysis. The group said it will release its examination of his plan as soon as Thursday.

All of the candidates seem to think tax simplification is the key to voters' hearts.

Carly Fiorina who has not yet offered a tax plan, said she would reduce the tax code, estimated to run some 73,000 pages, to just three.

“Because only if it's about three pages are you leveling the playing field between the big, the powerful, the wealthy and the well-connected who can hire the armies of lawyers and accountants and, yes, lobbyists to help them navigate their way through 73,000 pages,” she said. “Three pages is about the maximum that a single business owner or a farmer or just a couple can understand without hiring somebody.”

In the party’s so-called undercard debate, Bobby Jindal defended his call to require everyone to pay federal income taxes.

Jindal, who said millions don't have a stake in controlling federal spending because they don't pay income taxes, has proposed requiring everyone to pay at least two percent.

Asked about workers who pay Social Security and Medicare payroll taxes even if they don't pay income taxes, Jindal said: "You're talking about payroll taxes that fund programs, people pay for their Medicare, they pay for their Social Security - I want every American to worry and care about how those folks in D.C. are spending our money."