Immigration issues bring out the worst instincts in politicians who should know better. The US Congress showed that earlier this year. Now it is the turn of France’s Parliament. It is moving toward final approval of an ugly new law that would introduce DNA testing as a potential basis for excluding prospective immigrants hoping to join family members already living in France.

DNA testing can be a useful tool in establishing criminal guilt or innocence. But it has no rightful place in immigration law. The DNA provision, proposed by a member of Parliament close to President Nicolas Sarkozy, has been angrily denounced by the center-left opposition, principled members of the center-right majority and a member of Sarkozy’s Cabinet.

Though himself the son of a Hungarian immigrant, Sarkozy has made his political name with harsh criticism of more recent immigrants, especially North African Arabs. His pandering on this issue helped win him votes that used to go to far-right extremists like the perennial presidential candidate Jean-Marie Le Pen. Immigrant bashing is an effective vote-getter. Unfortunately, it leads to bad laws, bad policies and needless human suffering for the individuals and families it targets and exploits. Sarkozy wants to be seen as a statesman. He should act like one.