HERE’S A question for Homeland Security Secretary John F. Kelly, who seems to regard himself as a bystander in the impending showdown over the fates of nearly 800,000 undocumented youngsters raised and educated in the United States, who may face deportation if Congress fails to act.

Mr. Kelly, don’t you have a voice?

The secretary, a battle-hardened former Marine Corps general, has assumed a posture of virtual impotence as anti-immigrant right-wingers in Texas and elsewhere threaten legal action that would leave “dreamers” vulnerable to deportation. They would do so even though the young people — mainly teenagers and 20-somethings who have lived at least a decade in the United States — were brought here illegally as children, through no fault of their own.

Back in February, Mr. Kelly addressed lawmakers and said, “I would just beg you . . . to change the law” so that protections against deportation for undocumented youngsters, granted five years ago by President Barack Obama, were not rescinded. Since then, however, he has sounded increasingly passive, suggesting that there is little he can do to protect them.

In fact, there is. Legislation that would codify the protections granted dreamers by Mr. Obama has been introduced in both the Senate and the House of Representatives, with bipartisan sponsorship. The legislation is known as the Bridge Act — the acronym stands for Bar Removal of Individuals who Dream and Grow our Economy — and while Mr. Kelly has been briefed on it, he has not endorsed it.

Why not? Commendably, the secretary appears to have little appetite for deploying Immigration and Customs Enforcement deportation agents to round up hundreds of thousands of youths, most of whom are in school or employed and have no personal memory of any country but the United States. He has been told by lawyers that Mr. Obama’s executive order granting dreamers temporary, renewable two-year deferrals from deportation, along with work permits, may not withstand the legal challenge threatened by Texas Attorney General Ken Paxton (R) and officials of about 10 other states.

Yet he has made no explicit call for Congress to enact the Bridge Act, which, like Mr.­ Obama’s 2012 executive order, would shield dreamers from the threat of deportation, in this case for three years, thereby taking “that particular issue off the plate,” as Mr. Kelly suggested to lawmakers in February.

As for President Trump, he has waffled on the issue, having as a candidate called for rescinding the Obama order, then in January suggesting dreamers “should be far less worried,” then more recently saying the issue is “always tough.” He, too, should make clear that Congress would do the country a favor if it let these young people continue to contribute to the nation’s economy and welfare.

Some officials say the administration will defer to Attorney General Jeff Sessions, a pro-deportation hard-liner. But Mr. Kelly’s department oversees deportations and would have to cope with the upheaval that would be unleashed on families and communities by a mass deportation of youths, most of whom are American in every sense but their birth. His word would carry weight.