It’s uncomfortable to accept that terrorists have declared war on the free world. After recent terrorist attacks in San Bernardino, Calif., and Paris, however, we have no choice but to accept it.

Monday marked the 74^th anniversary of Pearl Harbor: The moment when a global war was viciously thrust upon every single American. While mourning the dead in the attack’s aftermath, the United States immediately joined – and led – a momentous struggle to save the world from tyranny.

As the new Amazon TV series The Man in the High Castle brings to life in vivid, terrifying detail, history could have been much different. Had the U.S. and its allies lost World War II, future generations would have almost certainly faced mass murder, enslavement and indoctrination at the hands of evil, totalitarian regimes.

Our country’s Greatest Generation did not seek war. In fact, millions of Americans wanted nothing to do with the struggle before Dec. 7, 1941. Upon recognizing the enormous stakes, however, our country’s leaders – along with ordinary citizens – quickly rose up to defend liberty. Seventy-four years later, with our way of life facing another grave threat, we must come together in that same patriotic spirit.

For the military community, 9/11 was our generation’s Pearl Harbor. Ever since that horrific day, courageous Americans have been stepping forward to serve and sacrifice in harm’s way. If you visit any military cemetery or veterans hospital, you will bear witness to the enormous toll of 14-plus years at war.

After spending the last five years speaking with and writing about military heroes, I can report – without a shred of doubt – that bearing war’s burdens has brought incomprehensible grief and hardship into the lives of many U.S. troops, veterans and their families. Still, despite the risks, these remarkable Americans chose to sacrifice relative comfort in defense of others.

In a three-week period, we watched in horror as civilians in Paris and San Bernardino were murdered and maimed by terrorists with links to ISIS. Over and over again, the terrorist organization has shown that it will murder, rape, or torture anyone who doesn’t fall in line with ISIS’ evil, twisted vision.

It’s time for all Americans to realize that terrorists have declared war on each and every one of us. If presented with the opportunity, ISIS will almost certainly target our country’s Democratic president and Republican leaders in Congress. At the same time, terrorists will continue murdering civilians of all religions, races and ethnic backgrounds. And yes, that includes innocent, defenseless children.

Is it comfortable to read, write, or talk about these terrible realities? Of course not, but to ignore or diminish the threat posed by ISIS and other terrorists is not only dangerous: It’s reckless. What if the World War II generation had chosen comfort over combat? As The Man in the High Castle chillingly conveys, our country’s streets might have ended up being controlled by foreign soldiers and secret police.

Indeed, it’s uncomfortable to recognize that more than 14 years after 9/11, another terrorist attack was just carried out on U.S. soil. It’s uncomfortable to realize that in order to defeat ISIS and other terrorist groups, more Americans will die. It’s uncomfortable to accept that while targeting terrorists where they operate, innocent civilians will be caught in the crossfire.

Like the Greatest Generation and the heroes of our post-9/11 military community, Americans did not ask for this fight. For the sake of our children and grandchildren, though, we must unite behind the cause of defeating terrorism, once and for all.

Tom Sileo is a senior editor of The Stream and co-author of Brothers Forever: The Enduring Bond between a Marine and a Navy SEAL that Transcended their Ultimate Sacrifice.