The last vestige of hope we had that Vladimir Putin might turn out to be a leader we could work with has vanished.

Russia's president Friday signed a parliament-passed ban on the adoption of Russian children by Americans. This is not only a cruel blow to many children, some of whom already had met their adoptive-parents-to-be, but has greatly exacerbated tensions with the United States.

More than 60,000 children from Russia have been adopted by American citizens since the Cold War ended. The current rate has been about 1,000 a year.

Most of these children have been happily assimilated into their new families and live far better than if they had grown up in overcrowded Russian orphanages. Some arrived with serious illnesses and are doing well. Many have gone on to college.

A sad case in 2010 of a troubled young boy sent back to Russia by an American woman who said she could not cope with him resulted in a Russian outcry. Russia said because the United States refused to ratify the 1989 Convention on the Rights of the Child, Russian children are not safe in the United States.

But that is not why Putin signed the ban on adoptions. (There is a now-void Russia-U.S. agreement to safeguard the rights of children adopted internationally.)

Putin wanted to retaliate against the Obama administration for signing a law Dec. 14 barring Russian human rights abusers from traveling to or having financial transactions in the United States.

Putin's venom also spewed out at nongovernmental organizations with U.S. funding, now banned from political activity in Russia. This will further chill democratization efforts, including freedom of the press.

The measure will bar some Americans from entering Russia on grounds they have violated human rights, as defined by the Putin government, and will suspend their business operations in Russia.

There is more to this impasse than Putin's childishness. American conservatives who refuse to engage in diplomacy with Russia or to ratify United Nations actions such as protecting children and more recently protecting the rights of the disabled, are also to blame.

The lives of hundreds of children and their would-be parents have been saddened immeasurably, and the U.S.-Russia relationship is badly strained. Furthermore, it hurts President Barack Obama's efforts to win Russian support to end the bloody civil war in Syria.