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Marco Rubio has been selling a bipartisan plan on immigration, but Ann Coulter isn't buying it.

One day after Rubio entered the conservative lion's den to talk immigration reform on Rush Limbaugh's radio show, Coulter blasted the GOP senator in a Human Events column.

"Some Republicans seem determined to create more Democratic voters, too. That will be the primary result of Sen. Marco Rubio's amnesty plan," Coulter wrote. She was voicing a campaign-politics concern that Limbaugh also alluded to, that allowing unauthorized immigrants to apply for citizenship would legalize 11.2 million new Democratic voters. Democrats only want immigration reform, the theory goes, in order to expand their voter base.

Coulter writes:

Rubio's bill is nothing but amnesty. It isn't even "amnesty thinly disguised as border enforcement." This is a wolf in wolf's clothing. Despite all the blather about how Rubio demands "Enforcement First!" the very first thing his proposal does is make illegal aliens legal. (Don't call them "illegal aliens"!)

… and blames California's budget problems on Hispanic voters, warning that the nation will go bankrupt if Rubio has his way:

With Hispanics on track to become the largest ethnic group in California this year, the state that gave us Richard Nixon and Ronald Reagan is incapable of electing any Republican statewide anymore. Taxes keep going up, and there's no one left to pay the bill. That will be our entire country if Republicans fall for Rubio's phony "Enforcement First!" plan. Perplexingly, some Republicans seem determined to turn the whole nation into California, in the foolish hope of winning one last election.

The "amnesty" label is a tough one to shed, and if that gets attached to the bipartisan Gang of Eight bill that Rubio is pushing, the Florida senator could have a much tougher time selling it to his fellow conservatives.