America's problem with illegal immigrants has gone unsolved for years, largely because the enforcement methods needed to crack down thoroughly would be Draconian and many of the immigrants fill low- wage gaps in the US economy.
Those same constraints operate in Europe, where the problem is similar in scope. An estimated half-million illegal migrants enter the European Union each year in search of work, mainly from Africa, the Middle East, and the Balkans. Thousands more come seeking political asylum.
An added constraint for the EU is that 15 nations are trying to cope with a vast flow of job-seeking humanity, rather than one.
EU members made a stab at working together to close the door on illegal entrants at their recent summit in Spain. What emerged were a few practical steps - and some clear differences over just how tough to get.
Few European leaders would disagree that something has to be done, since immigration is fueling resurgent right-wing politics in their countries. Most of the migrants are Muslims, which adds to concerns about terrorists filtering in.
But a move by Britain and …