I wrote a few weeks ago about Wal-Mart’s motivations for signing a letter endorsing a mandate requiring employers to purchase health insurance for their employees. Now it appears that the National Retail Federation has written its own letter distancing itself from Wal-Mart and the employer mandate. The letter is not only interesting in that it calls Wal-Mart out by name, but it is also one of the most prominent industry-wide stands against the government-heavy health-reform efforts in Congress. Given that the Democrats have had a few recent stumbles on this front, and are now saying that they won’t make their August recess deadline for completing the bills, this new development could be the first major rift in the Obama plan to keep industries allied with them or at least on the sidelines during the legislative process.