The Judas Solution by Timothy Zahn (Blackcollar 3)

The final and best of the Blackcollar books.

Timothy has some kind of pulp fiction feel to his stories and in the end reasonable men will win.

The plot is a multilayered one. The Blackcollars learn about a military headquarter being built on a human world that might contain the secret to victory and dispatch a team to deal with it. At the same time another team goes to earth to join up with Torch and the resistance.