See if you can get us good terms on joining the Federation.
In order to join the Federation, he must first make peace with you.
I wish we could get them to join the Federation.
The last, worst time for her had been just before he left to join the Federation.
At least we've standardized a few things since joining the Federation.
It never had anything to do with your planet joining the Federation.
They settled there about a hundred years ago, but never joined the Federation.
"This plague may well have happened even if you had not joined the Federation."
We'd had our eye on this system for some time, wondering if they might be ready to join the Federation.
When a world joins the Federation, it is a most serious occasion.