Earlier this month, five Chinese naval warships entered U.S. territorial waters off the coast of Alaska. In acknowledging the transit of these vessels, the United States made clear we viewed this action as well within the rights of China — and any other nation — to conduct innocent passage through the legitimately established territorial seas and nonthreatening military activities within the exclusive economic zone of another country.

This reaction stands in stark contrast to what has been happening recently in the Spratly Islands in the South China Sea. Over the past two years, China has embarked on an aggressive campaign to turn barren rocks into 2,000 acres of full-fledged artificial islands capable of hosting a range of long-range military activities. Even more concerning, it is increasingly possible China will use these artificial islands as a basis to assert wider, but legally unfounded, claims over vast swaths of the waters and airspace within this already highly contested area.

It should be lost on no one that China is trying to have it both ways — benefiting from the protection under international law known as the United Nations Convention on the Law of the Sea, or UNCLOS, to operate and transit near our territory in the first example, but ignoring that same agreement to make excessive and unfounded maritime claims that only serve to further undermine good order on the seas in the second.

I count myself among those in Congress who believe that a robust, forward-leaning response is needed to ensure responsible maritime nations in the region adhere to the rule of law. This includes increased freedom of navigation operations that rebuff any claim to territorial or economic rights for artificial land formations, while continuing to make clear the freedom of any nation’s military to operate outside of another’s territorial waters.

However, the current debate in Congress on the scale and scope of these operations misses a larger and more fundamental element. As I heard repeatedly when meeting with several senior naval officers in the Pacific earlier this month, our efforts to raise objections and enforce this rule of law are continually undermined by our failure to ratify UNCLOS. They shared their personal experiences of interacting with Chinese authorities who are quick to point out that our nation is one of only handful that has not ratified UNCLOS — and regularly use this fact to rebut our criticism of their island building.

Congress — and in particular the Senate — has been warned of the implications of its failure to ratify UNCLOS. Incoming Chief of Naval Operations John Richardson told the Senate Armed Services Committee that “by not acceding to UNCLOS, we deny ourselves the ability to challenge changes to international law as a result of the practice of nations at the local, regional, or global level.”

Adm. Harry Harris, our commander in the Pacific, stated that “acceding to the convention gives us the moral high ground to criticize those countries that would seek to inhibit freedom of maneuver in the oceans and airspace around the world, including the Asia-Pacific region.” And, as Gen. Joe Dunford, chairman of the Joint Chiefs of Staff, warned earlier this year, “We undermine our leverage by not signing up to the same rulebook by which we are asking other countries to accept.”

These are not new concerns. They were raised in 1994, 2007 and 2012 when the Senate considered ratification of UNCLOS — only to have it blocked time and again by members with a narrow and short-sighted opposition to the compact. Notably, in a 2007 Senate Foreign Relations Committee hearing, then-Vice Chief of Naval Operations Adm. Patrick Walsh stated that, “by acting from within the convention, we can best exercise our leadership to ensure that those rights and freedoms are not whittled away by foreign states.”

Unfortunately, years of obstruction in the Senate have ensured that China’s whittling away of the freedom of the seas that once seemed so far off is transpiring now — and without action, it will continue. In addition to undermining our efforts to challenge excessive maritime claims in the Pacific, there is a growing concern that the United States risks being left behind as China, Russia and others lay claim to the Arctic under the auspices of UNCLOS.

There is good reason why UNCLOS has been strongly supported by presidents and members of Congress on both sides of the aisle, a steady stream of military officials dating back to the 1980s, and a broad coalition with stakeholders from business, industry and trade. Simply put, it was and remains in our nation’s economic and security interest to ensure the rule of law and good order on the seas.

Alone, ratification of UNCLOS by the Senate will not change China’s course or resolve all maritime disputes in the region — but it will place us on most solid legal, diplomatic and moral ground when we uphold the freedom of navigation for the United States and our partner nations in Pacific. It is long past time to get this done.

Rep. Joe Courtney, D-Conn., serves as ranking member of the Seapower and Projection Forces Subcommittee.