I have followed with concern the news coverage of the brutal murder of American journalist James Foley by Islamic State terrorists. During the press conference addressing Foley’s beheading, President Obama appropriately diagnosed the group as a cancer that must be extracted, calling on all of humanity to unite in rejecting its “nihilistic ideologies.” President Obama struck the perfect tone in his remarks, appalled, yet resolute, outraged, while remaining clear-eyed, realistic, but still optimistic. It was Obama at his best.

Then he demonstrated the fecklessness so characteristic of his presidency. He rushed out of the press conference so as not to miss his 1 p.m. tee time. Unfortunately for the hundreds of millions of people looking to him for leadership in these troubled times, Obama’s incongruous haste to get back on the golf course gutted his own remarks, recasting the whole press conference as an Emmy worthy performance by a gifted, if not oblivious, actor.

In politics, like anything else, actions speak louder than words. Sadly, the horrific image of James Foley, kneeling in a orange jumpsuit with a knife held to his throat and the heart-rending scenes as Foley’s parents mourned and praised and honored their son will be inextricably linked with the pictures of a fist-bumping Obama hamming it up with his celebrity golf buddies. Though he may loathe doing so, President Obama should follow the example of his predecessor, George W. Bush, and give up golf entirely until after his presidency. The president needs to show with both words and deeds that he is deadly serious about protecting Americans from the Islamic State group. In 2017, after he has handed the reins to another, he can golf in peace every day for the next 40 plus years of his taxpayer-funded retirement.

Now back to the terrorist group formerly known as ISIS and ISIL. U.S. Secretary of Defense Chuck Hagel acknowledges that it is “an imminent threat to every interest we have,” that its combination of fanaticism and sophistication is “beyond anything we’ve seen.” Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, argues, “This is an organization that has an apocalyptic end-of-days strategic vision that will eventually have to be defeated.” They both know what they are talking about.

The Islamic State group is a cancer. It does not build. It only destroys. If it is allowed to carve out an Islamic caliphate, glutting itself on Iraq’s oil wealth, it will metastasize and spread throughout the world, bringing disease and death to free societies. We must be determined, along with the other peoples of the world, to keep it from spreading, isolate it, and eradicate it. The United States should continue to support the Iraqi Army and the Peshmerga Militia in their efforts to defeat this group. We must not shrink from what needs to be done.

All the while, we must realize that this enemy will not hesitate to bring the fight to us here in the United States. These terrorists are almost certainly among us. An estimated 2,000 such militants have Western passports. Most of them joined the Islamic State fighters by flying to Turkey and sneaking across the border into Syria. While do-not-fly lists may stop them from traveling directly into the United States, our southern border is wide open and these guys know how to blend in.

Within the last few days, several Twitter messages were posted, showing landmarks in Chicago and Washington, D.C. with Islamic State group flags held up in the foreground, and with the disturbing message, “We are in your state. We are in your cities. We are in your streets. You are our goals anywhere.”

We must steel ourselves for what is to come.

Dan Liljenquist is a former state senator and U.S. Senate candidate.