When Republicans start lying like Democrats, you can guess they are pushing an idea that’s bad for America. During his William Ginsburg-like tour of the Sunday talk shows last weekend, Sen. Marco Rubio was the Mount Vesuvius of lies about his immigration bill.

Here is how Rubio explained the powerful border-enforcing mechanism in his bill on “Fox News Sunday,” which he denied was merely a meaningless goal:

“Basically, Homeland Security will have five years to meet that goal. If after five years, Homeland Security has not met that number, it will trigger the Border Commission, who will then take over this issue for them.”

So the water torture awaiting the Department of Homeland Security if it fails to secure the border is … ANOTHER GOVERNMENT COMMISSION WILL BE CREATED! Take that, Homeland Security! Ha — we have you now!

The only thing more frightening than “another government commission” is a “strongly worded letter.”

Rubio said his comprehensive immigration plan isn’t amnesty because “amnesty is anything that says ‘do it illegally, it will be cheaper and easier.'” But, he assures us, it’s “cheaper, faster and easier for people to go back home and wait 10 years” — as the law currently requires — “than it will be to go through this process that I’ve outlined.”

Then why is he doing it? If it’s “cheaper, faster and easier” for illegals to apply for citizenship under current law, what exactly does Rubio’s plan accomplish?

Is it to encourage illegals to go home and apply through normal channels? You know, since that’s so much easier. Then why does he oppose enforcing the law on the books now? He dismisses enforcement of current law as trying to make “life miserable to them so that they’ll self-deport,” which he claims won’t work.

Does his plan make them just a little bit miserable so maybe some of them will “self-deport”? (Which doesn’t work, according to him.) Or is he lying about it being “cheaper, faster and easier for people to go back home”?

Rubio keeps trotting out the canard about the bounty of taxes we’re going to collect from millions more minimum-wage workers when illegals are legalized, stoutly asserting: “In order to keep this legal status, you must be gainfully employed and you must be paying taxes.”

It’s as if he’s talking to someone who has never been to America and is unfamiliar with its tax system.

By “paying taxes,” Rubio means “filing a tax return and getting a payment back from the government in the form of the earned income tax credit.” Another term for what Rubio calls “paying taxes” is “receiving welfare” — which newly legalized illegals will start receiving right away under Rubio’s plan. The only tax they’ll pay is the same tax they pay now: sales tax.

But, incomprehensibly, Rubio swore up and down that the newly legalized illegal immigrants won’t get government benefits: “And then they don’t qualify for any federal benefits. This is an important point. No federal benefits, no food stamps, no welfare, no Obamacare.”

How on Earth does Rubio plan to enforce this “important point”?

Just three weeks ago, the U.S. Senate voted down a proposal to prevent illegal immigrants from receiving benefits under Obamacare. At the time, Democratic Sen. Bob Menendez sneered at Republicans opposing Obamacare for illegals, saying, “This is not a great way to try to do your outreach to the Hispanic and immigrant community.”

Forcing Republicans to spend the next two decades arguing that poor Hispanic children shouldn’t have access to government benefits like health care and food programs sounds like a terrific way to win over the Hispanic vote!

Is it going to be easier or harder for Republicans to deny welfare to 20 million newly legalized illegal aliens than it is for them to simply say that people who have broken our laws should not be on a fast-track to citizenship?

Also, is Rubio planning to stop his newly legalized illegal aliens from having children? The children of illegal aliens become automatic citizens under our current insane interpretation of the 14th Amendment.

(It seems that, after the Civil War, what the framers of the 14th Amendment had at the top of their agenda was not invalidating the Dred Scott decision and confirming the citizenship of former slaves, but ensuring that, a century hence, the children of any foreigners who manage to sneak into the country illegally and give birth would become full-fledged U.S. citizens.)

As I’ve noted before, Hispanic women have a higher illegitimate birthrate than any other ethnic group in the country, including blacks. Currently, 71 percent of illegal immigrant households with children collect federal benefits.

In California — which will be America if Rubio’s plan goes through — 82 percent of households headed by an illegal immigrant are on welfare, as are 61 percent of households headed by legal immigrants, according to the March 2011 Current Population Survey by the Center for Immigration Studies.

If you think Republicans are Hispandering now, wait until the children of 20 million illegal aliens start to vote. Rubio’s amnesty isn’t just bad for America, it’s the end of America.

Ann Coulter is an author and political commentator.