Matthew Yglesias challenged those academics who signed the economists' open-letter on immigration to endorse scrapping the H1B visa system "and instead allow unrestricted immigration of foreign college professors." "If there's really no difference between 'us' and 'them' economists should be leading the charge to disassemble the system of employment protections they enjoy," writes Yglesias. No problem, say Brad DeLong and Greg Mankiw (via Daniel "Bring It On" Drezner).