The next president faces potentially catastrophic challenges: a runaway national debt that threatens to crash the economy and destroy the opportunities of young Americans; an economy that seems sluggish and halting despite years of job growth; a belligerent Russia playing extremely dangerous games with its military; a rising China probing for weakness in the West; a crazed regime in North Korea ramping up its capacity to deliver nuclear missiles to America; a meltdown in the Middle East with the rise of groups determined to export terror. It is little wonder that a large majority of Americans believe the nation is going in the wrong direction.

In this environment, there is one candidate who has the intellect, calmness, toughness and experience to lead America through these troubled times. That is why we enthusiastically endorse Democrat Hillary Clinton for president.

Ms. Clinton, who turns 69 this month, is a seasoned Washington player who needs no training in operating the levers of power. She was a first lady and a lawyer in Arkansas, a politically active first lady of the United States, a U.S. senator and a secretary of state. She knows how the presidency works, how the Congress works, how foreign policy works and how states interact with the national government.

She has made clear she understands the vital importance of American engagement in the world. Our safety — and that of all free people — cannot be secure if the United States tries to hide from the harsh realities of the world. She has been a defender of democracy and human rights around the world.

While she has retreated on free trade during the ongoing campaign, she has long recognized that it is in the United States’ vital interest to do business with the world, helping to spread capitalism and sell our products while lifting impoverished people out of misery. America’s future will be grim indeed if it cannot make the most of its creativity and technological know-how in world markets, something Ms. Clinton’s major-party opponent would threaten.

She can be counted on to defend the rights of women, protecting their full participation in our society. As the first woman president, she would serve as an inspiration to young women, and a welcome sign that there are no barriers to achievement. Ms. Clinton recognizes that diversity helps strengthen America.

The next president will confront a divided country and quite possibly a Republican House. Gridlock — driven by a fierce partisanship that is fueled by campaign contributions — has for years made it difficult to solve problems in Washington. While holding to strong Democratic beliefs, Ms. Clinton seems to be a pragmatist at heart, capable of bringing people together to solve problems. She is clearly respected by members of both sides of the aisle. We remember that after her extravagant plan to overhaul health care during her husband's first term went down to defeat, she rolled up her sleeves and helped enact health-care reform to help poor children.

We suspect a similar approach could be used to push through such politically difficult measures as long-overdue infrastructure work, repairing Obamacare, immigration reform, stronger gun laws to protect Americans, making Medicare and Social Security sustainable, and reforms to our criminal justice system. Each of these would require grueling work and an ability to refrain from attacking political enemies, but if Ms. Clinton has demonstrated anything in her career, it is dogged persistence in achieving her goals.

We don’t agree with Ms. Clinton on everything. The Iran deal was a very bad one, in our view. Her campaign proposal of taxpayer-funded college for everyone is a non-starter and utterly impractical, especially given the national debt. We have long expressed concerns about her problems with openness and accountability, notably in operating a private email server that allowed her to delete records she did not want the public to ever see. (She has been open with her tax records, on the other hand.)

Far and away, Ms. Clinton is the best in the field of candidates this year. Americans can be proud to elect her on Nov. 8 to become America’s first woman president.