Is it good for Marco Rubio?

That was the question in the political world this week, after Scott Walker dropped out of the GOP primary due to an empty wallet and zero popular support. The logic is that Walker and Rubio were on a similar track. They were younger members of the party who could plausibly please the conservative base without scaring away the establishment. So Walker's demise could only spell good things for Rubio.

I don't see it that way. Rubio's strategy should be to rise slowly, outlast his other conservative opponents, and create as clear a one-on-one shot at Jeb Bush as he can get. Walker's early departure hurts that strategy, by removing a candidate who, like Rubio, has danced around the issue of immigration policy. This risks raising Rubio's profile early enough that his conservative opponents, including Ted Cruz, Bobby Jindal, and Rick Santorum, can hammer him on his previous support of "comprehensive immigration reform," which is Beltway speak for amnesty. And of course, Donald Trump can do the same too, once Rubio rises to his notice.

And they can make him pay a price. It's hard to overstate how unpopular amnesty is not just with Republicans, but with Americans as a whole. A 2007 California Field poll found that 46 percent of respondents supported a policy of "having federal immigration agents round up, detain, and deport immigrants found to be living here illegally." Needless to say, a policy of mass forced expulsion is far stricter than Mitt Romney's supposedly extreme support for workplace enforcement that leads to attrition and "self-deportation" of undocumented immigrants.

A well-publicized study in 2012 found that as Americans learn more about the number of such immigrants in the country, their support for tough enforcement and for lowering overall immigration into the U.S. increases. When stated in even remotely neutral terms, Americans oppose measures to liberalize immigration by overwhelming margins. In the midterm election exit polls, restrictionist positions were supported by margins running nearly four to one.

Rubio has backtracked from his support of the "Gang of Eight" bill that passed the Senate in 2013 but never passed in the House. He has said he learned a lesson — and will be tougher next time. Rubio got hammered this week for supposedly abandoning his earlier liberal positions, and saying that under his preferred system a path to citizenship would not be available for more than a decade. In fact, this is not substantially different from the full 13-year waiting period in the Gang of Eight bill.

Even if he backs away from that bill, his support for it will be fair game. That piece of legislation will become a piñata for any candidate with the sense to whack it. The undercooked law has scores of bullet points that will make fine lines in any attack ad in Iowa or New Hampshire. Here are just a few that occur to me:

Marco Rubio's immigration bill had no effective mechanisms for enforcing America's border, but contained a $150 million giveaway to the ACLU to help illegal aliens get amnesty.

Marco Rubio's amnesty bill immediately granted legal status to millions of illegal aliens, and proposed only one consequence if the federal government failed to secure the border in the next five years: the creation of another committee of bureaucrats appointed by Washington, D.C., to make more recommendations.

At a time when America was suffering from high unemployment, Marco Rubio worked with liberal Chuck Schumer on an amnesty bill that doubled the amount of foreign workers coming into America.

Marco Rubio's bill created a financial penalty for employers who hired Americans, and made it cheaper for them to hire amnestied illegal aliens.

Marco Rubio's amnesty bill removed federally mandated "check-in/check-out" points for anyone coming in to America over a land border.

Marco Rubio claimed that his amnesty bill would make illegal immigration a thing of the past. But the CBO estimated that over the next 20 years, his bill would only reduce the rate of illegal immigration by 25 percent.

Under Marco Rubio's amnesty bill, one in five people in America in 2033 would have been born in a foreign nation.

A skilled politician with a lot to gain can do enormous damage to a candidate on this issue. See the way Mitt Romney thrashed Rick Perry over in-state tuition for undocumented immigrants in 2012. Or even the way Hillary Clinton was hurt when Barack Obama criticized her support for driver's licenses for immigrants in his first presidential run. Democrats can read a poll, too. They know as well as Republicans that amnesty is popular among people who can imagine themselves hiring amnestied immigrants, not among those who can imagine competing with them for work.

Marco Rubio should be praying that his rise in the polls does not occur until every immigration hawk in the race has dropped out — and he is only facing Jeb Bush.