Sen. Jeff Flake’s bill to enshrine the DACA program in law would also make the illegal immigrant “Dreamers” eligible for Obamacare — including perhaps hundreds of millions of dollars in taxpayer subsidies to buy health plans, Congressional scorekeepers said this week. Mr. Flake, Arizona Republican, tried to power his bill through the Senate on Tuesday, but was blocked by another senator. His bill would offer those who qualified for the original DACA program a new, three-year legal status, which would include permission to work in the country legally, in exchange for $7 billion — or about three year’s worth of...