The person who explains every failure away may be preparing an explanation for yours.

Somebody who has an explanation ready for every setback, always locating the cause somewhere outside themselves, is showing you their method. The bad market, the difficult client, the previous team: the account is prepared, and it never lands anywhere near them. When something goes wrong alongside you, that same machinery runs, and you are conveniently placed to become part of the story. How they speak about absent people is the preview.

Keep your agreements with such a person written down and dated. Notice who gets blamed this month, because that is the seat you may be sitting in later.