The Trump administration scored a legal victory allowing it to lift an exemption for tariffs on certain imported solar-panels after being thwarted for months in court.

A U.S. trade judge on Thursday ruled that a proclamation the president issued in October to close the loophole for two-sided, or bifacial, panels doesn’t violate an earlier court order.

The White House’s victory may be fleeting. While the move paves the way for the tariff exemption to be lifted, Judge Gary Katzmann said solar companies that have fought to keep the exemption can file a new lawsuit to block Trump’s proclamation.

While tariffs on imported panels have been a boon for a handful of U.S. manufacturers, they’ve driven up costs for companies that build solar farms. Those developers welcomed the exemption on two-sided panels and fought for it remain in place.

First Solar Inc., the largest U.S-based panel manufacturer, rose as much as 4.6%. China-based JinkoSolar Holding Co., meanwhile, fell as much as 4.9%.

The administration has tried for more than a year to terminate the bifacial exclusion but it’s been repeatedly blocked by the trade court. In October, Trump moved again to eliminate the loophole—this time via a proclamation. In it, the president said, the exemption has “impaired and is likely to continue to impair the effectiveness” of tariffs intended to bolster U.S. solar manufacturing.

In 2018, Trump approved four years of tariffs on solar panel imports, starting at 30%. The following year, his administration surprised many in the sector when it granted an exclusion for bifacial panels. While they were considered niche products, the tariffs had encouraged some new solar manufacturing in the U.S., and module imports exempt from those duties posed a threat.

The case is Invenergy Renewables LLC v. U.S., 19-192, Court of International Trade (New York).