Missouri has joined the effort to create national common standards, so now only three states are not on board. The holdouts are Alaska*, South Carolina, and Texas.
The District of Columbia, Puerto Rico, and the U.S. Virgin Islands have also agreed to take part.
An Aug. 7 press release (tweeted by @ASCDpolicy) says that the Missouri state board of education voted on Aug. 6 to join the common standards initiative. Earlier this summer, Missouri Gov. Jay Nixon, a Democrat, had announced his commitment to the undertaking.
*corrected from earlier version
A version of this news article first appeared in the Curriculum Matters blog.