The Teamsters union is withholding an endorsement for Democratic presidential candidate Hillary Clinton, further eroding Clinton’s support from Big Labor.

The Teamsters union’s general executive board voted unanimously Tuesday, 26-0, to hold off on endorsing Clinton at its meeting in Charleston, South Carolina. Fox News reports that the vote was meant as “an intentional snub” of Clinton for backing away from her previous support for the job-creating Keystone pipeline.

The union is holding off until union-friendly Vice President Joe Biden makes a decision about whether or not to run for president.

The union also seeks a “sit down” meeting with Republican presidential candidate Donald Trump, whose recent tax reform proposal drastically lowers the corporate and individual tax rates for the middle class in an effort to spur job growth, savings, and investment.

Clinton’s relationship with Big Labor has been rocky.

Last month, the National Nurses Union endorsed Democratic challenger Bernie Sanders over Clinton.

AFL-CIO head Richard Trumpka threatened to sit out the 2016 election until Clinton backed away from her support of President Obama’s Trans-Pacific Partnership (TPP) trade deal, which unions strongly opposed.