You've found them. You know they're out to at the very least destroy your lives if not outright exterminate your species.
How many times have you stopped -- the "old fashioned way" -- Magneto (with and without Acolytes) and/or Sinister and/or Trask and/or Apocalypse and/or any number of other genocidal lunatics at the cost of how many lives and how much collateral damage and how much setting back of your cause everytime these fights go public?
What do you do when you can no longer afford that cost?