Start with 2007, when a coalition of Republican and Democratic senators came up with a bill that also enjoyed the support of the Bush White House. It wasn’t perfect, but it extracted compromises from each side—e.g., enhancements for border security, a guest-worker program, and the inclusion of the entire Dream Act, the legislation for children who’d been brought here illegally that Mr. Obama claims he has always wanted.

Sen. Obama opted to back 11th-hour amendments that Kennedy rightly complained were really intended as deal-breakers. At a critical point, Kennedy urged that President Bush ask then-Senate Majority Leader Harry Reid to keep the Senate in session to get the last few votes the bill needed. Mr. Reid opted for the Obama approach: Concluding he’d rather have the political issue than actual reform, he adjourned the Senate for the July 4 recess.

A year later Mr. Obama was running for president. Before the National Council of La Raza, he vowed: “I will make [comprehensive immigration reform] a top priority in my first year as president.” Yet notwithstanding the lopsided Democratic majorities he enjoyed in Congress his first two years, he didn’t push for immigration legislation, which makes his promise to La Raza rank right up there with “if you like your health care plan you can keep it.”