A woman holds up a sign outside the U.S. Capitol in support of the Deferred Action for Childhood Arrivals (DACA) program on Dec. 5. (Jacquelyn Martin/AP)

Tim Cook is chief executive of Apple. Charles Koch is chairman and chief executive of Koch Industries.

The holidays are upon us, and families across the United States are coming together to celebrate. Yet for about 690,000 of our neighbors, colleagues and friends, this holiday season is marked by uncertainty and fear.

These are the "dreamers" — children of undocumented immigrants who are working, in countless ways, to make the United States stronger. Unless Congress acts, this holiday season might be the last one the dreamers get to spend in the country they love and call home.

We must do better. The United States is at its best when all people are free to pursue their dreams. Our country has enjoyed unparalleled success by welcoming people from around the world who seek to make a better life for themselves and their families, no matter what their backgrounds. It is our differences that help us to learn from each other, to challenge our old ways of thinking and to discover innovative solutions that benefit us all. To advance that prosperity and build an even stronger future, each successive generation — including, today, our own — must show the courage to embrace that diversity and to do what is right.

We have no illusions about how difficult it can be to get things done in Washington, and we know that people of good faith disagree about aspects of immigration policy. If ever there were an occasion to come together to help people improve their lives, this is it. By acting now to ensure that dreamers can realize their potential by continuing to contribute to our country, Congress can reaffirm this essential American ideal.

This is a political, economic and moral imperative. The sooner Congress resolves this situation — on a permanent basis — the sooner dreamers can seize the opportunity to plan their lives and develop their talents.

This extraordinary set of circumstances has brought the two of us together as co-authors. We are business leaders who sometimes differ on the issues of the day. Yet, on a question as straightforward as this one, we are firmly aligned.

As a matter of both policy and principle, we strongly agree that Congress must act before the end of the year to bring certainty and security to the lives of dreamers. Delay is not an option. Too many people's futures hang in the balance.

Both of our companies are fortunate to have dreamers on our teams. We know from experience that the success of our businesses depends on having employees with diverse backgrounds and perspectives. It fuels creativity, broadens knowledge and helps drive innovation. For our nation to maximize progress and prosperity, we need more, not fewer, talented people at the table.

Another foundation of our country's success is our consistent and equal application of the law. In a free nation, individuals must be able to trust that when our government makes a promise, it is kept. Having laws that are reliable is what gives people the confidence to plan their futures and to invest in their businesses, their communities and themselves.

The United States should not hold hard-working, patriotic people hostage to the debate over immigration — or, worse, expel them because we have yet to resolve a complex national argument. Most Americans agree. In fact, more than 8 in 10 Americans support a straightforward solution to allow dreamers to stay.

No society can truly flourish when a significant portion of its people feel threatened or unable to fulfill their potential. Nor can it prosper by excluding those who want to make positive contributions. This isn't just a noble principle; it's a basic fact, borne out through our national history.

Dreamers are doing their part. They have shown great faith in the United States by coming forward, subjecting themselves to background checks, and submitting personal and biometric data.

Now, the rest of us need to do our part. Congress should act quickly, ideally before year's end, to ensure that these decent people can work and stay and dream in the United States. As a nation, we must show that the dreamers' faith in our word and goodwill was not misplaced. And we should make clear that the United States welcomes their contributions as part of our national life.