Not necessarly. There will need to be other indicators,the knowledge of only exists within buildings without windows, that need to come together. This is very delicate decision.
"This is very delicate decision."
Whether are not the threats are real, they can achieve a political effect (election and post-election) by introducing increased uncertainty and volatility into the national environment. Release information and one side will see a political motive. Withhold (even if there are good reasons), and others will also see an ulterior motive.
They need to ask the "Gang of Eight" to meet and lay the intel before them.
Ask them to come to a unanimous recommendation and go with it.
This operation seeks to achieve an "effect". The effect is not a result but an environment. They are seeking the same "effect" as on 9/11 (quasi-decapitation).
Get an established bipartisan group separate from the executive branch to back the decision and the psychological effect (charges of politicization either way it goes) is negated.