A federal judge in Washington expressed skepticism Thursday about whether the federal courts should jump into the middle of an “ugly dispute between the political branches” over the Trump administration plan to move around federal funds to build a border wall.

U.S. District Judge Trevor N. McFadden said that a House lawsuit to block the Trump administration’s spending was in “unusual territory,” since higher courts have never ruled on whether the legislative branch could sue the executive branch.

[Trump wants 400 TSA agents sent to the border. Democrats say that may hurt morale]

And McFadden said the issue of whether the House can bring the lawsuit at all “strikes me as a significant issue in this case.” He spent most of a three-hour hearing grappling with the broader separation-of-powers showdown over control of government spending.

The judge asked Douglas Letter, the House general counsel, whether the House “utilized all the tools at its disposal before rushing into court.” And at another point, McFadden asked, “There are other tools in your arsenal here, right?”