Why Shouldn't Illegal Immigrants Have to Pay Back Taxes?

National Review's Katrina Trinko reports Rand Paul saying an epically silly quote about not requiring illegal immigrants to pay back taxes:

Paul was uneasy with the idea of harsh financial penalties for illegal immigrants. “If you had to pay back all your back payroll taxes and you’ve been working here for ten years, that would be thousands and thousands of dollars . . . so to get your work visa, I wouldn’t have any kind of big penalty like that,” he remarked. “If you’re going to get in the other line for citizenship, if they’re going to make it real easy, like you get right into the green-card line, then maybe you have to have pay penalties.”

Thousands and thousands of dollars! Good Lord, it'd almost be like the United States believes people who work here should pay their taxes, and we certainly wouldn't want to give that crazy impression. Paul thinks it would be prohibitive for people to come up with payment for that large a fine. But we don't set fines for lawbreaking upon the ability of an offender to pay, so why should we make an exception for non-citizens who didn't pay their fair share of taxes as workers (albeit illegally) in the United States?

Requiring full repayment of back taxes as a prerequisite to getting in line for a green card should be a top priority for the GOP as we negotiate immigration reform. After all, fairness, right?