Former White House political strategist Karl Rove warned Senate Republicans in a meeting this week not to become overly reliant on their conservative base as they head into what could be a tough 2020 presidential election. Rove, who served as former President George W. Bushs top political strategist, was brought in by Senate GOP leaders to speak to the 22 Republican incumbents up for reelection at an all-day planning session Thursday hosted at Nationals Park in southeast Washington, D.C.