President Obama's recent decision to use executive order to bypass immigration laws is a lawless act, but it may end up being politically successful because it does raise uncomfortable questions for his opponents.
First, let's quickly dispense with any doubt about its lawlessness. The order was defended as "prosecutorial discretion" by Janet Napolitano, but discretion cannot meaningfully apply in this case. Suppose a Republican president issued an executive order directing federal authorities to stop enforcing penalties on capital gains tax collection (as John Yoo suggested) or federal assault weapon laws. Would there be any doubt that such an order would be interpreted (correctly) as an attempt to bypass Congress? The Obama order should be viewed identically. Prosecutorial discretion is when a prosecutor uses discretion in an individual case. The executive order applies to an entire class of people.
The problem for Republicans, though, is that many of the people who would be helped by the executive order are sympathetic figures. The media has predictably singled out the straight-A students and success stories among them, but one can easily sympathize with any kid brought to the U.S. at a young age and now facing deportation through no fault of his or her own. However, it's for just such stories that prosecutorial discretion was invented. If the DHS chose - on an individual basis - not to deport in such cases, only the most hard-hearted would balk. Republicans need to emphasize this: that the problem isn't one of sympathy, but of Obama's naked politicization of the problem by ignoring the law and issuing the order.
On a larger scale, the reason for the problem in the first place is the ease with which illegal immigration has occurred. It's because there are 800,000 such sympathetic cases that this is such a massive problem. If it were 800 it would never even be noticed. And the reason there are so many is that we have a major illegal immigration problem. It's temporarily been reversed by a stagnant economy, but that will change. Unless reform is implemented to stop future illegal immigration, eventually the problem will recur. One reason it's been difficult to create reform is that neither the left nor the right is willing to make many concessions: the left views illegal immigration as, frankly, good politics (immigrants in general trending leftwards) and the right wishes to avoid the aftermath of the Reagan Amnesty, which promised to legalize many immigrants with the quid pro quo that future illegal immigration would be enforced. The actual result of the amnesty was even more illegal immigration.
Romney has taken a pretty good line in his responses, avoiding fire-breathing while pointing out the legal problems with the President's order. That needs to continue. The best way to avoid this in the future is to make sure the current President is no longer in office come January 20, 2013.