Earl Warren,
Lumbermen's Mutual Casualty Company v…
“ It is petitioner's contention that the 'matter in controversy' here is the underlying tort liability of the alleged wrongdoer. If this were true, of course, no diversity of citizenship would exist between respondent and Mrs. Bowen, as the real party-defendant in interest. But the Louisiana courts have differentiated between actions brought by an injured party against the insurer alone and those brought against either the tortfeasor alone or together with the insurer. In the former action, the insurer is foreclosed from asserting defenses such as coverture, normally available to the tortfeasor. ”
