For a project I’m working on, I’m collecting examples of statements made by high-level Democratic officials (especially, but not exclusively, Barack Obama) before January 2009 that such and such is unconstitutional (e.g., using military force without congressional approval, use of executive signing statements) that those Democrats either flipped-flopped on publicly (in the case of the president, this could be by his actions rather than words) or have been silent on since 2009. Citations, please. You could list these in the comments or send examples to dbernste at gmu dot edu.
And note, I totally understand and accept that Republicans do the same thing when the White House flips their way. Feel free to note such examples in the comments, though they don’t happen to be useful to my project.