Maybe it is. After all, there is a precedent for a mass pardon--Jimmy Carter's pardoning of Vietnam draft resisters. And there is a precedent for pardoning even the highest crimes and misdemeanors--Gerald Ford's pardon of Richard Nixon's Watergate-related offenses. See? It's all bipartisan!
Moreover, it would be a legitimate extension of the President's authority into foreign affairs, via a specific power granted to him in the text of the Constitution. He can exempt anyone currently charged with or convicted of a state or Federal crime, so there's no federalism problem (and immigrant activists would be totally on-board with that). And he can then make it possible for millions of law-abiding human beings who are American in every sense, save from the perspective of international law, to lawfully adjust their status OR, if need be, temporarily relocate in order to obtain a status for lawful entry. In turn, this would allow Congress to focus on what it really WANTS to focus on--new visa numbers for the economy.
So what's the problem? Certainly not Obama, who seems to be, lately, in a pardoning kind of mood.
I guess it's our beloved Republican Congress, which would rather have the re-election issue than the solution that benefits all Americans.
Don't believe the polls. Do yourself and all of us a favor, and throw out the REAL bums this fall--the ones on Capitol Hill!