その案は

that proposal

→ 其の
phrase Rare #40,463
that proposal その案 means “that proposal” or “that plan,” and は marks it as the topic of the sentence.
JA: その案はみんなに好評だった。
EN: That proposal was well received by everyone.

その案は具体化された

The plan was fleshed out.

その案は通った

That proposal was approved.

その案は使えなかった

That proposal wasn't usable.

その案は承知できない

I can't agree to that proposal.