For Romney, it was his shameful posturing in the Republican primary contests when he lurched to the right and not only took a hard line on anything resembling "amnesty" but also denigrated hardworking immigrants as takers who come to America for the freebies.
For Obama, it is his shameful record in office that includes 1.5 million deportations, divided families, thousands of U.S.-born kids of deported parents dumped into foster care, battered wives deported after calling the police, and expanded Arizona-style cooperation between local police and U.S. immigration officials nationwide by way of the Secure Communities program.
To avoid being criticized for all this by Latino supporters, Obama, Homeland Security Secretary Janet Napolitano and White House official Cecilia Munoz -- the administration's designated Latina apologist -- insist that it is only undesirables who are being deported. Meanwhile, community activists in Detroit are protesting what they claim is a serious infraction by the local field office of Immigration and Customs Enforcement, where agents are accused of staking out an elementary school to detain parents as they pick up their kids.
In trying to navigate the choppy waters of the immigration issue, each candidate has his coping mechanism. Obama retreats into a fantasy world of unicorns and cotton candy where immigration officials only deport -- as he said during the debate Tuesday at Hofstra University -- "criminals, gangbangers, people who are hurting the community" and not students or "folks who are here just because they're trying to figure out how to feed their families."
Back in the real world, ICE agents have deported, since Obama took office, hundreds of thousands of gardeners, housekeepers, nannies and farm workers who were just "trying to figure out how to feed their families."
Meanwhile, Romney prefers to keep his answers vague, especially when asked what he would do with the estimated 10 million illegal immigrants in the United States. If he gets specific, he might slip the mask and reveal what he really is: a pro-business, loose-enforcement, free-flow-of-labor kind of guy whose whole removal strategy consists of asking illegal immigrants to please "self-deport" while telegraphing the fact that he is not going to round up and deport those who refuse to leave.
During the second debate, Romney passed up multiple opportunities to slam Obama for stretching the truth. Such as when the president talked about so-called Dreamers -- undocumented students pursuing higher education -- deserving a "pathway to citizenship." Obama said he gave them that pathway "administratively."
Correction: Never happened. The Deferred Action for Childhood Arrivals program is explicitly not a pathway to citizenship. It is temporary; applicants are given a two-year work visa but can still be deported at any time by immigration officials.
Let's consider the awkward position that each candidate has put his supporters in. Team Obama has to feign outrage over Romney's plan to allow illegal immigrants to voluntarily leave the country while ignoring the fact that Obama prefers the more hands-on method. Team Romney -- in a futile bid to win Latino support -- is trying to criticize Obama for breaking his 2008 campaign promise to pursue comprehensive immigration reform, while ignoring the fact that, at least until the debate, the Republican candidate opposed the concept. Now Romney says that he'll "get it done" in his first year.
Really, what's the point of Obama and Romney bickering over immigration to see who is the lesser evil? On this issue, they're both dreadful.
Ruben Navarrette Jr. is a columnist for the San Diego Union-Tribune.