Rule 60 Intervenor's Pleadings

If you believe you have a stake in a lawsuit that is already going on, you can join that case by filing your own legal paperwork with the court. You do not need permission from the other parties to do this.

However, the other parties can ask the judge to remove you from the case. If the judge agrees there is a good enough reason to kick you out, your paperwork can be thrown out and you will no longer be part of the lawsuit.