If that's the way it goes, we have a serious problem.
When it was Holder being slapped with a contempt of Congress, it never went to court because (we were told) it simply could only be sent to the DOJ as a referral and we all knew how that was going to go. And that's exactly how it did go and where--nowhere.
If Dems can on there own take this kind of thing to court independently, we were lied to about how the DOJ was able to stop the Holder Contempt Citation and referral in its tracks.
If it goes to court the Democrats might have to answer some questions about their motivations under penalty of perjury.
There is one reason why the Democrats want the tax returns - partisan politics.