To be fair, you don't earn it. Security clearance =/= credibility. Clearance is a measure of "How probable is it that a foreign government might be able to bribe or blackmail this person?" Things that will get security clearance denied are posting foreign government sympathy on social media, having significant debt and thus be increased vulnerability to bribes, skeletons in the closet that might be blackmail-able, etc.

Having clearance just means they have investigated and found no glaring issues that they are more susceptible to foreign influence or an ability to keep a secret than normal. The college interns who answer the phones and send form replies in emails get clearance, I severely doubt they've done anything to 'earn' it.