This week, Missouri Gov. Eric Greitens signed into law Missouri’s new Right-to-Work Act. At roughly the same time, Republican Reps. Steve King of Iowa and Joe Wilson of South Carolina introduced the national Right-to-Work Act that would amend the National Labor Relations Act and the Railway Labor Act to remove language allowing unions to require membership as a condition of employment.

Republicans, including King and Wilson in 2015, have tried to push a national right-to-work bill through Congress without much success. But given President Trump’s endorsement of right-to-work laws during the campaign, and with Republican control of the House and Senate, 2017 might prove to be different.

Gov. Greitens’ action makes Missouri the 28th right-to-work state. The act is effective Aug. 28, 2017, and will not affect existing contracts between unions and employers until they reach their expiration date, at which point they will no longer be able to contain “union security” provisions. A prior right-to-work effort in Missouri passed the legislature, but was vetoed by then Gov. Jay Nixon.

The Kansas City Star reported that immediately after the bill was signed, organized labor took steps to block the implementation of the act. Missouri AFL-CIO President Mike Louis and Missouri NAACP President Rod Chapel filed a petition for referendum. If they can collect enough signatures by the act’s effective date, the law will be placed on a referendum ballot and implementation will be blocked until a vote is taken in 2018. To get the block, they will need to collect signatures totaling 5 percent of the voters from two-thirds of the state’s congressional districts, roughly 90,000 signatures.