Judging from the fact that the Retired Emperor launched Jokyu no ran (a war between the Retired Emperor Gotoba and Kamakura bakufu in Jokyu era) by taking advantage of Sanetomo's death, it is too hasty to conclude that Sanetomo was "a pro-imperial general."
上皇が実朝の死を好機と見て承久の乱に踏み切ったことから見ても、単に『親朝廷の将軍』と判断するのは早計である。