Citations needed. The primary argument used against ACA's constitutionality was struck down by the supreme court [1]. And there already exists at least 50 government agencies that reserve the right to pass regulations without congressional approval [2].

1: http://www.huffingtonpost.com/2012/06/28/supreme-court-affor...

2: http://usgovinfo.about.com/od/uscongress/a/fedregulations.ht...