The complete story about this is in the Missouri thread in the Political Forum but it seems Hoffa has now gotten involved.

(KANSAS CITY, MO) – Teamsters General President James P. Hoffa joined Missouri Gov. Jay Nixon and Missouri AFL-CIO Secretary-Treasurer and House Minority Leader Jake Hummel at a rally in Kansas City, Mo. today to support a bipartisan coalition of lawmakers working to uphold the governor’s veto of right-to-work legislation.

Hundreds of union members from across the state showed their support at the rally as Hoffa and Nixon pledged to continue the fight to keep so-called right-to-work legislation out of Missouri.
Nixon vetoed HB 116 in June after the Missouri House passed the bill by 92-66 and in the Senate by a vote of 21-13. Supporters of the bill need a two-thirds majority vote to overturn Nixon’s veto.