An untold, but significant story of President Trump’s White House has been the sharp contrast between the National Economic Council and the National Security Council.

The National Security Council has been nothing but trouble. It has churned through a series of national security advisers — Michael Flynn, H.R. McMaster, John Bolton, and now Robert O’Brien. On their watch President Trump did follow through on some campaign promises — moving the American embassy in Israel to Jerusalem and withdrawing from the Iran nuclear deal. He’s won the return of some Americans who had been held overseas.

Progress on other items — a nuclear deal with North Korea, a peace deal between Israel and the Palestinian Arabs, extrication of American troops from Afghanistan and Syria — has been slow, complicated, or nonexistent. The National Security Council even arguably is at least partially to blame for getting Mr. Trump mired in the House impeachment inquiry, with its staff reaction to the president’s dealings with Ukraine.

The National Economic Council, on the other hand, has, under both Gary Cohn and Larry Kudlow, been notable for its lack of drama. And who can argue with the results? The stock market has soared to record highs, and the unemployment rate has dropped to a 50 year low.

Some might say that Congress or the Federal Reserve deserve credit, or that it’s somehow a continuation of an upward trend that began under President Obama. For sure, though, if the stock market were plunging and the unemployment rate were soaring, Congress and the Obama team would be blaming the Trump White House.

President Trump has noticed the difference. He’s shrinking the size of the National Security Council staff by encouraging “detailees” — employees of the CIA, the Defense Department, the State Department, or other agencies who are temporarily assigned to the White House — to leave the National Security Council and return to their home departments. On issues that have both economic and national security components — say, China trade, or Iran’s oil — the National Economic Council is increasingly taking the lead, even though it is a much smaller operation.

What accounts for the different outcomes from the two similarly structured councils? Messrs. Cohn and Kudlow deserve some credit for the National Economic Council’s successes. They both came in with substantial private sector experience. Mr. Kudlow is exceptional in terms of his personal optimism and graciousness. They both had the advantage of working with Treasury Secretary Steven Mnuchin, who has also emerged as a strong player in the administration.

The national security team has not gotten along as well, hampered from the start by Defense Secretary James Mattis and Secretary of State Rex Tillerson, who never quite clicked with Mr. Trump. Mr. Tillerson’s successor, Mike Pompeo, has done better but may step down to run for the Senate from Kansas, in part as a way of positioning himself for an eventual presidential run.

The real explanation, though, has to do with Mr. Trump himself, and the way he looks at the world. The President doesn’t see the current national security landscape as particularly threatening to America, at least in comparison to the Cold War. The countries that others see as threats — Iran, North Korea — Mr. Trump kind of shrugs off, figuring that if he wants to, he could nuke them. One may disagree with that assessment, but that is how Mr. Trump sees it.

Mr. Trump does see the world, and the current challenges and opportunities for America, more in economic terms. Perhaps it’s the result of a career that Mr. Trump spent trying to accumulate wealth and work his way up the Forbes magazine rich list, but Mr. Trump sees the world in terms of which country gets the most money. That explains all the time spent on negotiating trade agreements with Canada, Mexico, China, and Europe. Economic warfare, the President understands. He doesn’t just understand it, he cares about winning at it.

There are risks to this approach. The American economy, after all, is too diverse and large and complicated to be managed directly from the White House. There are moments in history, as in the confrontations against the Axis, the Soviet Union, or al Qaeda, when national security in the traditional military understanding of the term demands a president’s full attention.

There is wisdom to this approach, too — an economically strong country will be a more secure one, the thinking goes, because it can afford a strong military and because countries around the world will want to be its partner.

For now, though, as Trump heads into an election year, the economic story is the one at which he’s winning. If he’s planning a campaign or a second term that plays to his strengths, economic policy, not national security, is where the action will be.