But by extraconstitutional means and for extråconstitutional ends.
Western legal tradition has long recognized that no constitution is a suicide pact, meaning an affirmative action that is procedurally unaccounted for in a constitution's text (note that the arrest of Allende was not barred by the Chilean constitution either though) may nonetheless be a constitutional act when it is necessary to save that constitution from complete destruction.
Of course, that is not what happened. And you'd be hard-pressed to find an informed observer of Chile who would say that Pinochet intended to preserve the Chilean constitution. The fact that he didn't is perhaps the strongest evidence.
The Chamber of Deputies' recognized that, and the strong endorsement of the coup given by virtually all non-Allendist officials in Chile served to affirm it.
Sounds like you're favoring the tyranny of a politically correct majority over the rule of law.
Not really. Eduardo Frei Montalva concluded as much. Considering that he was President of Chile from 1964-1970 and a leader of the center-left CDP at the time of the coup, you'd be hard pressed to argue that he was not an informed observer of Chile.
The fact that he didn't is perhaps the strongest evidence.
Your history is mistaken yet again. By the time of the coup the Chilean constitution was already in shreds due to Allende. Pinochet set about to restore constitutional government almost immediately. In 1976 he convened a constitutional commission consisting of the country's most respected political leaders including 2 former presidents, and tasked them with drafting the document. It was completed in 1979 and put before the voters, where it was approved, in 1980. Pinochet abided by its terms and voluntarily yielded office to an election in 1990.
Sounds like you're favoring the tyranny of a politically correct majority over the rule of law.
You've yet to show what "rule of law" gave sanction to Allende in 1973. In fact, you've yet to establish your original comment on this topic, namely that you considered Allende "legitimate."
A ruler's legitimacy is a prerequisite of his power under the rule of law. If Allende was not a legitimate ruler at the time of the coup, then overthrowing him cannot be a violation of the rule of law.