Media labor union Communications Workers of America (CWA) has sent a letter to the Federal Trade Commission (FTC) in support of Microsoft's seismic $68.7 billion acquisition of Activision Blizzard.

The group, which earlier this year helped Raven Software QA workers unionize despite alleged interference from Activision Blizzard, previously called on the FTC to "closely scrutinize" the deal and claimed it could lead to an "undue concentration of market power."

Specifically, the CWA was worried the deal might "exacerbate worker disempowerment and wage suppression," and make unionization more difficult.

Since raising those concerns in March, however, the CWA has entered into a labor neutrality agreement with Microsoft that will allow Activision Blizzard workers to "freely and fairly make a choice about union representation."

That agreement will come into effect 60 days after Microsoft's acquisition of Activision Blizzard has closed, and it seems the CWA is now satisfied that workers' rights will be protected following the deal.

"We now support approval of the transaction before you because Microsoft has entered an agreement with CWA to ensure the workers of Activision Blizzard have a clear path to collective bargaining," wrote CWA president Christopher Shelton.

"Microsoft’s binding commitments will give employees a seat at the table and ensure that the acquisition of Activision Blizzard benefits the company's workers and the broader video game labor market."

The CWA said its labor-management compact with Microsoft is notable because it reflects a shared understanding that the current labor law regime "doesn't deliver on the rights it professes to guarantee."

"Workers who seek to form unions in the United States today face severe barriers to exercising basic rights of freedom of association, with frequent firings of union supporters well-documented but not discouraged through any meaningful consequences," continues the letter, which levels multiple union-busting allegations at Activision Blizzard.

"When quality assurance testers at Activision Blizzard subsidiary Raven studio sought to form a union and requested voluntary recognition, management refused and instead attempted to stymie workers’ ability to achieve certification of their union with multiple aggressive tactics now under investigation by the National Labor Relations Act (NLRB).

"The Raven QA workers persevered and now they are headed to the bargaining table where they have the ability to exchange proposals, discuss market conditions, and share first-hand experiences between workers and management. The outcome will be a better workplace that can lead the industry in high-road practices that incorporate worker voice."

Given the progress that has been made since March, the CWA now feels that workers can be "assured" the transaction won't undermine the legal principle or broader antitrust laws pertaining to labor markets. As a result, it now intends to support approval of the transaction, which also gained shareholder approval back in April.