Jackson, J., dissenting
harden in the revolving drum and cause significant damage to the concrete ready-mix truck.” Id., at 9. But Glacier’s own submissions in Washington state court suggest that the Union instructed the drivers to return their trucks to Glacier’s yard after the strike began and to keep the ready-mix trucks running. See id., at 34, 77. Glacier’s submissions also suggest that those precautions actually provided the company’s managers and nonstriking employees with sufficient time to decide how to address the situation to prevent any harm to the trucks. See id., at 13, 72, 77, 82–83.
Was any risk of harm to the trucks here “imminent,” given the allegation that the Union instructed the drivers to keep the trucks running? Is the risk of concrete hardening in a delivery truck “aggravated,” in the way Marshall Car Wheel contemplates? Was returning the trucks to the employer’s premises and leaving them running a sufficient “reasonable” precaution, because it gave the employer sufficient time to address any risk of harm? Making the call about whether the NLRA protects the Union’s conduct raises these questions and others. Importantly, these kinds of questions not only involve making nuanced factual distinctions but also demonstrate that applying the Board’s reasonable-precautions precedents is, at bottom, a line-drawing exercise. Under circumstances like these, a court can confidently declare that a union’s conduct is not even arguably protected for Garmon purposes only where the allegations make out a clear Fansteel claim or where the alleged facts implicate a reasonable-precautions case that is directly on point. Because neither is true here, the Court should have concluded that the Union’s conduct was at least arguably protected.
Even if the Court’s task under Garmon were to apply the Board’s reasonable-precautions principle to the allegations of Glacier’s complaint and decide whether or not the Union engaged in unprotected conduct (to reiterate: that is not the assignment, see Part III–A, supra), I cannot agree with the
