From this Christian Science Monitor article with the damning title “Russian TV calls Tulsi Gabbard ‘our girlfriend.’ Can she keep US secrets?” we learn that she (1) harbors some skepticism about whether Syrian President Assad ordered the use of chemical weapons during the civil war, (2) thinks the war in Ukraine could have been avoided had NATO not pursued expansion, (3) has praised NSA leaker and whistle-blower Edward Snowden, and (4) opposed Section 702 of the Foreign Intelligence Surveillance Act that enables mass surveillance of US citizens. On the face of it, none of these views are strictly disqualifying. Some are laudable and certainly preferable to some of the policy positions of the current DNI, Avril Haines: Peace Groups Blast Biden’s DNI Pick Over Links to Drones, Torture, and Mass Surveillance.
There was a time when Tulsi Gabbard was an anti-war Democrat, but she was complicated then as well: The New Yorker, What Does Tulsi Gabbard Believe?