The effect of political Governor or party on Renewable Portfolio Standard adoption is examined across 50 U.S. states from 2001 to 2024. Using fixed-effects panel regression with clustered standard errors, it is found that persistent Democratic control has a small positive and statistically insignificant effect on RPS adoption (β = 0.047, SE = 0.045). While lagged party control shows a statistically significant impact. Specifically, two(β =0.004) and three(β =0.006) year Democratic control lag is associated with higher RPS levels compared to Republican control, which affirms policy lag hypothesis. Electricity prices show a positive result with RPS (pre-2009: β = 0.035, p < 0.05; post-2009: β = 0.018, p < 0.05). In contrast, the effect of GDP per capita remains mixed and statistically insignificant. The Hausman test confirms the superiority of the fixed-effects model over random effects (χ² = 49.53, p < 0.001). Structural break tests using the Bai–Perron method identify two major shifts in 2007 and 2015, while Chow tests indicate that the effect of party control on RPS did not significantly differ before and after 2009 (χ² = 0.93, p = 0.335). These results affirm the policy feedback framework, highlighting that institutional inertia and lagged political influence shape renewable policy outcomes over time. Finally, Bai-Perron multiple structural break test to investigate the temporal variability in the factors influencing Renewable Portfolio Standards (RPS) adoption across U.S. states from 2001 to 2024. The findings of this study contradict the null hypothesis of parameter stability, thereby identifying two statistically significant structural breaks in 2007 and 2015.