If the US Congress ever votes to permit a State to declare bankruptcy (which they have not) and if SEIU takes it all the way to the US Supreme Court because their attorneys think that the 10th and the 11th Amendment to the US Constitution do not authorize a Federal Judge to tell a sovereign State what to do and if SCOTUS rules against them, then that Federal law might permit bankruptcy.  

Except that the US Constitution prohibits "Impairment of Contracts" as well.  

That's assuming that the Democrats in Oregon who rely on SEIU and the other unions to support their re-election would ever do such a thing in the first place and that a referendum which talked about all the widows who would lose their benefits didn't overrule the Legislature.

"Firemen and police widows sue State of Oregon!"  Great headline!