As a result of continued resentment against Daoud's autocratic rule, close ties with the USSR and economic downturn because of blockade imposed by Pakistan, Daoud Khan was asked to resign. Instead of resigning, Daoud Khan requested King Zahir Shah to approve new 'one-party constitution' proposed by him which would in turn increase the Daoud Khan already considerable power. Upon rejection, Daoud Khan angrily resigned. The crisis was finally resolved with his forced resignation in March 1963 and the re-opening of the border in May. Pakistan continued to remain suspicious of Afghan intentions and Daoud's policy left a negative impression in the eyes of many Tajiks who felt they were being disenfranchised for the sake of Pashtun nationalism. He was succeeded by Mohammad Yusuf.