They've talked about consolidating for, like, centuries, it seems, and early today the two unions announced an agreement that will make it happen - assuming members from the two actors unions sign off on the deal. Support for the idea began to build in 2008 after AFTRA suspended its longtime bargaining partnership with SAG and worked out a separate TV contract. Nasty business at the time. From the LAT:
The split hurt SAG's bargaining leverage and its coffers, as producers swung most new prime-time TV shows to AFTRA because it was perceived as the more stable union. The splintering of work between the unions has taken a toll on actors as well. Many have complained that it is tougher for them to earn the minimum pay necessary to maintain or qualify for health and pension benefits because their work is increasingly divided between SAG and AFTRA.
They still have to present the plan to the two boards. Ratification may happen by April.