In 1205, he eliminated senior vassals Shigetada HATAKEYAMA and his son based on the charge of treachery and tried to put Tomomasa HIRAGA, his son-in-law, in the position of shogun in cooperation with his second wife Maki no Kata (Lady Maki) in July of the same year (in the lunar calendar); however, his attempt was thwarted by the opposition of his son Yoshitoki HOJO and daughter Masako.
1205年（元久2）には有力御家人の畠山重忠父子を謀反の罪で滅ぼし、さらに同年旧暦7月には後妻の牧の方と共謀して娘婿にあたる平賀朝雅を新将軍として擁立しようとしたが、子の北条義時と政子の反対にあって失敗した。