Guardian: In its half-century history, the EU has absorbed wave upon wave of immigrants. There were the millions of political migrants fleeing Russian-imposed communism to western Europe throughout the cold war, the post-colonial and "guest worker" migrants who poured into western Europe in the boom years of the 1950s and 60s, the hundreds of thousands who escaped the Balkan wars of the 90s and the millions of economic migrants of the past decade seeking a better life. Now, according …