President Obama’s top immigration enforcer, John Morton, recently instructed his officials to take mitigating factors into account, like an immigrant’s family ties in the United States and education status, when deciding which deportation cases to pursue. It was not a major breakthrough, but it was sensible and humane, which is why it drew the ire of Representative Lamar Smith, who thinks Mr. Obama is too soft on illegal immigrants.

Mr. Smith, who heads the House Judiciary Committee, on Tuesday introduced a bill to suspend the executive branch’s ability to use discretion in immigration cases. He would not suspend it for every president, just this one.

In a memo to colleagues, he said his proposed law would expire at the end of Mr. Obama’s term, when it would “restore these powers to the next president whom the American people elect — on January 22, 2013.”

The idea behind the discretion is that immigration officials cannot go after everybody, so it makes sense to focus resources on people worth worrying about, like drug dealers, gang members and violent criminals. This is standard practice everywhere in law enforcement.