> I am arguing this didn't give him a mandate to initiate the radical reforms he undertook<
He was elected with particular policies, which he sought to implement, that does suggest a mandate.
In securing the support of Congress the Popular Unity government co-signed with the Christian Democrats a Statute of Constitutional Guarantee. That serves as the only additional restriction, other than what existed as part of the Chilean constitution.
"Specifically, the agreement guaranteed the existence of opposition political parties, and of the armed forces as a nonpartisan and autonomous institution subject only to the president's control in his role as chief-of-state. Organized social groups such as labor unions were guaranteed their autonomy and multiparty character, as were the key institutions of the university, the private school system, and the communications media. The liberal-democratic freedoms of speech, assembly, and religion also were affirmed."
The Politics of the Allende Overthrow in Chile, Peter A. Goldberg https://www.jstor.org/stable/2148700 Political Science Quarterly, Vol. 90, No. 1 (Spring, 1975), pp. 93-116
no subject
He was elected with particular policies, which he sought to implement, that does suggest a mandate.
In securing the support of Congress the Popular Unity government co-signed with the Christian Democrats a Statute of Constitutional Guarantee. That serves as the only additional restriction, other than what existed as part of the Chilean constitution.
"Specifically, the agreement guaranteed the existence of opposition political parties, and of the armed forces as a nonpartisan and autonomous institution subject only to the president's control in his role as chief-of-state. Organized social groups such as labor unions were guaranteed their autonomy and multiparty character, as were the key institutions of the university, the private school system, and the communications media. The liberal-democratic freedoms of speech, assembly, and religion also were affirmed."
The Politics of the Allende Overthrow in Chile, Peter A. Goldberg
https://www.jstor.org/stable/2148700
Political Science Quarterly, Vol. 90, No. 1 (Spring, 1975), pp. 93-116
The Allende government fulfilled those requirements. The Pinochet régime did not.