Left: Difference between the effective and free three-body potentials for the $K=1$, $K=3$, and $K=5$ grand-angular momenta in the $1/2^-$, $5/2^-$, and $9/2^-$ three-proton wave functions, respectively. Right: For the same p--p--p states, the function $f(\rho)=(m/\mathchar'26\mkern-9muh^2)(V_\mathrm{eff}(\rho)-V_\mathrm{free}(\rho))\rho^3$ is shown which asymptotically goes to the $\zeta$ constant in Eq. \ref{veff}.