This is fact.
The law can be overturned through normal congressional procedures, but as long as it is law it must be funded.
If the Republicans succeed in forcing President Obama into a defunding debacle then that will be overturned in the courts immediately by the first citizen who claims harm. Fact.
This not like other government shutdowns which were mostly fiddling and diddling over small money here and there. This is economic suicide on behalf of partisan politics by the Republicans!