The formerly angry faction, Trump supporters, are now optimistic, and the former sunny optimists, Clinton supporters, are now angry, but net contentiousness seems about the same. That’s a problem for business leaders because for employees the stress of this environment is exhausting, and deep political tension at work can warp the culture, freeze collaboration, and wreck productivity.

Apple CEO Tim Cook has again proved himself a leader with the message he emailed to all U.S. employees Wednesday. A note urging employees to put partisan feeling aside and “move forward together” could have been standard corporate blather, but Cook astutely made it do double or triple duty, and it’s an instructive example for all leaders.

Specifically:

—He framed employees’ differing views of the candidates as an example of Apple’s diversity and inclusiveness: “We have a very diverse team of employees, including supporters of each of the candidates,” he wrote. That framing was effective because it was authentic. Cook has built a record of defending inclusiveness, for example publicly criticizing proposed laws in Arkansas and Indiana last year that some believe would have legalized discrimination against LGBT citizens. “Apple is open for everyone,” he has said. “We welcome everyone.”

—He reminded employees that they all work together for a noble purpose: “Our products connect people everywhere,” he wrote, “and they provide the tools for our customers to do great things to improve their lives and the world at large.” Too many business leaders miss this opportunity—explaining how the company makes the world a better place. The best leaders do it relentlessly.

Cook tied this point to the issue of political divisiveness by observing how Apple (AAPL) achieves its noble purpose: “Regardless of which candidate each of us supported as individuals, the only way to move forward is to move forward together,” he said. That is, by putting their differences aside, Apple employees can accomplish something valuable that they could never do alone.

—In the trauma and stress of the election, he identified an opportunity for employees to help one another. This was brilliant, done in a single sentence near the end of the note: “I’ve always looked at Apple as one big family and I encourage you to reach out to your co-workers if they are feeling anxious.” Cook is turning powerfully felt political opinions from fuel for anger into an opportunity for empathy and human connection. He’s suggesting that employees focus on each other’s emotional state rather than on each other’s partisan stance; to the extent they actually do that, the atmosphere is transformed from blistering heat to comforting warmth.

Sending an email won’t make tense disagreements evaporate. But done right, it can make everyone in the organization more self-aware and can start the job of detoxing the workplace.

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