Her interest in Marxism led to an investigation by the House Un-American Activities Committee and Blair was blacklisted for some time, but resumed her career with a critically acclaimed performance in Marty (1955) for which she was nominated for an Academy Award for Best Supporting Actress.
Hendes interesse for marxisme førte til en undersøgelse fra House Un-American Activities Committee og Blair blev sortlistet i nogen tid, men genoptog sin karriere med en kritikerroste præstation i Marty (1955), at vinde en BAFTA Award og en nominering til en Oscar for bedste kvindelige birolle.