Jim Kirk was, at that moment, sitting at his computer, trying to write Spock a letter of recommendation. He'd written literally dozens of these before, but he wanted to give Spock the best recommendation possible for his new position. It was the least he could do, and it barely felt adequate. Especially because everything he wrote just couldn't express what he wanted to say.
Dear Sir,
I am writing to you on behalf of Commander Spock. As I am sure his commendations tell you, he has served with distinction-
No, no, that was too impersonal; it made it sound like he didn't know Spock at all, or care.
Dear Sir,
I have served with Commander Spock for three years. In that time, I have never seen-
How could a letter sum up three years of depending on someone to keep you alive, of watching out for someone, of working so well together they could predict each other's actions? Those few words could hardly describe how Kirk trusted Spock more than anyone he'd ever met, how they understood each other so well they didn't need to speak aloud; just a glance. How Spock was the best friend he'd ever had. Kirk sighed and gave up for the moment, turning instead to look at which officers were available to take the first officer's position. Anderson, no, he'd only ever served on a starbase. Kirk wanted someone with a little more deep space experience. Clark, no his record was full of instances of fighting, looked like he had a temper. After three years of having a Vulcan First Officer, Kirk wasn't sure he could serve with someone like that. Douglas, his record made it look like he needed a baby-sitter more than a captain. With every name, Kirk had to remind himself that he was only replacing his First Officer, not his friend. It didn't make much difference. Kirk was honestly unsure whether he could serve well with someone else, even as he was aware what a failing this was as a captain. He'd grown used to Vulcan levels of punctuality and efficiency; to being able to trust his life to Spock without thinking, to always having that logical, rational opinion. As a command team, he and Spock were so in tune, he couldn't imagine trying to run the ship with anyone else. Asking someone to step into half of that command team was unfair, Kirk knew this, but that was what had to be done.
At least Bones was still here. And it wasn't like Spock was dying, just accepting another job. They'd still see each other, hear from each other. That was what Kirk told himself. In reality, he knew that once linked with the Medusan ambassador, he didn't know what Spock would be like. Kirk turned back to the list of officers without much enthusiasm. He simply couldn't picture himself with anyone else at his side.