Their argument is that longshore labour disruptions impose significant costs on US supply chains and need to be addressed.

The PLUS revisions would amend the National Labour Relations Act (NLRA) and Labour Management Relations Act (LMRA) to include two specific unfair labour practices by longshore worker unions.

These practices would subject the unions to civil damages from employers.

The first unfair act would involve engaging in a labor slowdown, even when a collective bargaining agreement is in effect.

The second would prohibit unions from impeding port modernisation efforts or interfering with the servicing of automated vessels operating without a crew.

This proposed legislation comes shortly after west coast waterfront employers and the International Longshore and Warehouse Union (ILWU) reached a tentative deal for a new six-year coast wide labor contract following contentious negotiations lasting 13 months.

During these talks, the ILWU engaged in port slowdowns to gain leverage, which particularly impacted time-sensitive shipments, such as those from agricultural exporters.

As a result, there have been calls for increased federal intervention in port labour disputes.

The senators supporting the PLUS act highlight the significant financial losses experienced by Idaho businesses due to labour union slowdowns.