WOMEN IN THE U.S. military have been on the front lines of two wars. They’ve engaged the enemy, suffered grievous injury and been awarded medals for valor; 152 of them have died. So the Defense Department’s decision to lift its official ban on women in combat is, in some respects, an acknowledgement of reality. Nonetheless, it is a historic move — both sobering and exhilarating — that affirms the importance of women in defending this country and removes barriers that have impeded them in that work.

“The fact is they have become an integral part of our ability to perform our mission,” Defense Secretary Leon E. Panetta said Thursday as he announced an end to a policy that essentially restricted women from serving in the infantry, artillery, special operations and other specialties. The decision to upend a rule in place since 1994 came on the recommendation of the Joint Chiefs of Staff, whose chairman, Gen. Martin Dempsey, joined Mr. Panetta in signing an order that will open hundreds of thousands of front-line jobs to female service members.

One result will be a more level playing field for women, who make up about 14 percent of active-duty personnel: As they seek to advance in rank, they will no longer be hobbled by lack of official combat credentials. Gen. Dempsey said that the change will also mitigate the military’s persistent problem of sexual assault and harassment: Having “part of the population designated as warriors and one as something else” has “in some way led to that environment.”

Neither of those benefits would justify the change if it were to compromise military effectiveness. But most people knowledgeable about the situation believe that won’t happen. “American women are already serving in harm’s way today all over the world,” said Sen. John McCain (R-Ariz.). “It reflects the reality of 21st-century military operations,” said Sen. Carl Levin (D-Mich.), chair of the Armed Services Committee. Gen. Dempsey said that the change will be implemented in a way that won’t sacrifice the military’s capability.

Each branch of the military is charged with devising its own plan and will be allowed to seek exceptions if officials think there are positions that should remain closed to women. It’s important, as Mr. McCain added, that standards not be compromised. But the way in which female service members in Iraq and Afghanistan performed a range of jobs once thought unimaginable for them — from driving trucks down bomb-strewn roads to serving as gunners on vehicles — is evidence not only of their mettle but also of the military’s ability to properly train and deploy its troops.