The flat tax has dominated the tax-reform debate among the Republican presidential candidates in recent weeks, with well-publicized endorsements from Herman Cain, Rick Perry and Newt Gingrich, but not everyone is on board.

Michele Bachmann, the Minnesota congresswoman who has slipped from Tea Party darling to third-tier candidate, told ABC News that she would not support a flat tax because Ronald Reagan didn't support it.

Reagan didn't have one tax rate, Bachmann told interviewer Jonathan Karl. The principles that I'm borrowing from are Reagan's.

She confused the issue later in the interview, however, when she called her own plan a flat tax on the order of Ronald Reagan, even though, as she said before, it is not a flat tax.

Bachmann Intention: New Tax Code, Lower Marginal Rates

The details of her plan are still in flux, but the principle is to have fewer tax brackets and lower rates across the board.

My plan is to abolish the tax code and bring those rates down, she said. There will be more information forthcoming, but right now what I'm talking about are the principles. The principles are those that have worked.

Interestingly, Bachmann said in the same interview that the flat-tax plan Rick Perry released on Tuesday was based on her ideas.

Imitation is the most sincere form of flattery, and so we're grateful, Bachmann said. The ideas that I've been espousing -- again, lower the taxes rates, flatten it, make it far more simple, far less complex, but also make it so that the average American can fill out their taxes on a postcard -- I've been talking about this for months.

It seems, though, that she believes Perry took her ideas -- or, rather, Reagan's ideas -- too far.

Perry's plan would allow taxpayers to choose between their current rate and a new flat rate of 20 percent. That would ensure that nobody's tax rate increased, as low- and middle-income Americans' rates would under Cain's 9-9-9 plan, which would establish a 9 percent personal income tax, 9 percent corporate tax and 9 percent national sales tax.

But under an optional flat-tax system like Perry's, it would be impossible to raise the same amount of revenue as the current tax code, as Cain's plan ostensibly does.

The 9-9-9 plan has been received mostly negatively, even by Republicans, since several reports found that it would actually increase taxes for most Americans. Perry's plan has been criticized for not being revenue-neutral, but it has also gotten prominent endorsements from Americans for Tax Reform president Grover Norquist and Club for Growth president Chris Chocola.