A jogging shoe is seen at a makeshift memorial for the victims of the Boston Marathon bombings on Boylston Street in Boston, Massachusetts April 18, 2013. Reuters/Shannon Stapleton

This is now our too-familiar story. An explosion of violence at the heart of a great American city. Grieving over the death of innocents, and over the loss of a fragile sense of security.

Healing recognition that we are served still by heroic police and firefighters who run toward carnage, not away from it. And a recognition that we are searching still for the elusive balance between safety and liberty. Maybe this time, America can get it right.

That should be the goal in the aftermath of the April 15 bombing at the Boston Marathon. Even as we mourn the dead and tend to the wounded, Americans must be conscious that these are tenuous times. History tells us that in a rush to respond to tragedy, we have sometimes made grave errors of judgment and policy: scapegoating religions, ethnicities and ideologies; assaulting basic liberties; a militarization that deepens animosity instead of addressing it.

When a festive public event, a celebration of athleticism with no obvious political character, is targeted, a nation reconsiders questions of security. There’s nothing wrong with this; Franklin Roosevelt wisely identified “freedom from fear” as one of his four fundamental human rights. But America has often stumbled in the pursuit of security. After the 9/11 attacks, authorities approved a “Patriot Act” and embraced an intelligence-gathering regimen that former Senator Russ Feingold says failed to “protect the rights and freedoms of law-abiding Americans with no connection to terrorism.” Secret detention, “enforced disappearances” and torture—as the newly released report by the nonpartisan Constitution Project says—were approved at the highest levels of government. Washington looked abroad for monsters to destroy, following a path of military adventurism that, by conservative estimates, killed tens of thousands of innocents and realized the worst fears of John Quincy Adams, who had warned 180 years earlier against foreign engagements that would “involve [us] beyond the power of extrication, in all the wars of interest and intrigue, of individual avarice, envy and ambition, which assume the colors and usurp the standard of freedom.”

Barack Obama secured the presidency in 2008 with a promise to reject those doctrines. He has ended the Iraq War and begun preparations for withdrawal from Afghanistan, and he has eased tensions in many regions. Yet he not only preserved but expanded much of the Bush/Cheney national security state, aggressively pursuing greater surveillance, more drone strikes and weakened Miranda rights for domestic terror suspects.

It is indeed possible to be both safe and free, and in his best moments the former constitutional law professor understands this. In a measured response to the Boston bombing, Obama wisely avoided bombast, reminding Americans that they “shouldn’t jump to conclusions before we have all the facts.” Even as the facts are gathered, the president should work with Congress to provide public safety and infrastructure funding for cities that would enhance security while maintaining the freedom that defines city life. They can also set a standard that tells authorities at every level, in every community, that striking the right balance is not just necessary; it’s a fundamental American value.

Some years ago, in a moment of reflection, Obama said of terrorists, “They may seek to exploit our freedoms, but we will not sacrifice the liberties we cherish or hunker down behind walls of suspicion and mistrust. They may wish to drive us apart, but we will not give in to their hatred and prejudice.” Those are words to speak anew in this arduous moment, and to be linked with deeds, as we forge a response defined not by our fears but by our better angels.

In 2011, John Nichols wrote about some Democrats’ (and some Republicans’) belated objections to certain provisions of the Patriot Act, which President Obama was urging Congress to reauthorize.