Let \(S_j(t)=\pi ^{-1}\arg L(1/2+it, u_j)\), where \(u_j\) is an even Hecke–Maass cusp form for \(\mathrm SL_2(\mathbb {Z})\) with Laplacian eigenvalue \(\lambda _j=1/4+t_j^2\). In this paper, we establish an unconditional asymptotic formula for the moments of \(S_j(t)\).