More than two dozen Senate Democrats have told UPS and the Teamsters union that they will not intervene in the event the Teamsters strike UPS on Aug. 1.

In a letter sent late Wednesday to Teamster General President Sean O’Brien and UPS (NYSE: UPS) CEO Carol B. Tomé, the senators expressed hope that both sides can “negotiate in good faith and reach a consensus agreement that addresses basic human needs and allows workers to do their jobs safely and with dignity. However, in the event a fair and equitable collective bargaining agreement cannot be reached, we commit to respect our constituents’ statutory and constitutional rights to withhold their labor and initiate and participate in a strike.”

Earlier this week, about 175 House members, most Democrats but some Republicans, sent a similar letter to O’Brien and Tomé pledging not to intervene in the event of a strike.

The matter is covered under the National Labor Relations Act, which allows negotiations and subsequent actions to proceed generally without congressional intervention. Unlike the Railway Labor Act, which covers airlines and railroads, the parties need not jump through multiple legislative hoops before taking what are known as self-help measures such as a strike or a lockout. The current contract expires July 31.

“This growing group of elected officials, including Democrats, Republicans, and Independents, has committed to have our members’ backs if UPS fails us all by forcing workers out on strike August 1,” O’Brien said in a statement Wednesday night. “By saying they will not intervene, these officials are doing right by American workers and the labor movement. The power is in our own hands to negotiate the best contract, higher wages, and benefits.”

UPS was not immediately available to comment.

The Teamsters union has already asked the White House not to intervene in the negotiations. The White House intervened last year to prevent a rail work stoppage.

Talks between UPS and the Teamsters are expected to resume as early as Monday after a nearly three-week hiatus. Talks stalled July 5 over the issue of pay for thousands of UPS’ part-time workers. The Teamsters represents about 340,000 UPS workers.