THE NEWS conference that Secretary of State Rex Tillerson held Thursday with Japanese Foreign Minister Fumio Kishida looked rather unremarkable. The secretary paid tribute to the U.S.-Japan alliance in an opening statement and answered four questions from journalists, offering an intriguing but undefined suggestion of a “new approach” to the North Korean missile and nuclear weapons threat. The news conference was attended by American and Japanese journalists, among others.

But a closer look at Mr. Tillerson’s early conduct of the office suggests all is not normal. The appearance in Tokyo was the secretary’s first news conference since starting the job Feb. 2. He has yet to deliver a speech outlining U.S. policy. He broke with decades of practice and decided to make a major trip abroad without the contingent of reporters who regularly cover diplomacy and report to the American people. Instead, the department offered one seat on the secretary’s plane to a journalist from a conservative website, Independent Journal Review. The State Department’s acting spokesman, Mark C. Toner, said it was a cost-saving measure and due to the downsizing of the secretary’s plane, although journalists in the past have paid for airfare. The slimdown also could be intended to shield Mr. Tillerson from press scrutiny and basic discussion about important issues, which has been standard practice from Henry Kissinger’s time to today. Hopefully, Mr. Toner will be proved correct in his promise that “going forward . . . every effort will be made to accommodate a press contingent.”

There is a deeper concern here than press access. Mr. Tillerson’s reticence may be suitable for an oil company chief executive, but the job of chief diplomat of the United States comes with a responsibility to be a voice for the policies of the president, and the values and principles of the nation. It is often called “public diplomacy,” but that hardly does justice to the fact that eyes around the world are on the United States. A comment from the secretary can warn adversaries, guide decision-makers and keep allies motivated to support U.S. goals. The statement that the United States objects to the persecution of a lone dissident has saved more than one from long imprisonment and torture; the summoning of the world to respond to a crisis, such as famine and pandemic, is often critical in galvanizing support; U.S. policy toward military conflicts and confrontations is of maximum, urgent interest to adversaries and allies alike. There is something forceful and resonant about public declarations that can be more potent than those in private. Mr. Tillerson should not forsake this critical tool.

In bringing about change, words and deeds both count. Long experience teaches that clear messages as well as big guns are essential. Going silent is counterproductive and would reduce the role of the United States in the world.