Gov. Bruce Rauner last month established the Illinois Competitiveness Council, which will scrutinize occupational-licensing requirements and other regulations constraining economic growth. In targeting occupational licensing, Mr. Rauner has joined the Obama White House, several other governors, and commissions in states including Michigan, Virginia, Indiana and even regulation-happy California. But despite bipartisan support, licensing reform is likely to face ferocious opposition from members of licensed occupations.