With the clear momentum in the EU moving against ACTA, the supporters of the treaty in the EU Commission (who negotiated the deal) began to worry that the EU Parliament might move to reject ACTA completely at the vote planned for June. So they cooked up this delay tactic of taking ACTA to the EU Court of Justice to get a ruling on the legality of the document. However, some realized that a big part of the strategy behind this move was to try to push off the EU's vote, and hope that it could be brought at another time when the issue wasn't seen as such a political hot potato. It looks like that's not happening, and the EU Parliament has agreed (strongly) to move forward with the planned vote around June, and will not wait for the EU Court of Justice's opinion on the matter. So, for folks looking to stop ACTA in its tracks, the focus has to be on convincing MEPs to vote against it in June.