I really think that government employees should be considered to always be under oath. Any lie is perjury and needs to be prosecuted. Any federal employee who fails to fully prosecute a lying federal employee should be prosecuted. Work it up the chain so that these rats don't protect each other.
A truly Good Faith effort to tell the truth should always be mandated. Currently, law schools teach students to "lie well" as an essential job skill. Instead, law schools should teach students to "be always honest".
No more Clintonian "it depends on what the meaning of is is". The concept of "the truth, the whole truth, and nothing but the truth" should be taken seriously. No more dodging questions in front of Congress. Answer the question. If the questioner says it's "Yes or No" then answer "Yes or No" or face possible jail time.
One advantage of this would be that a great many people would be scared away from government jobs and government would have to be smaller.
They often exaggerate and sometimes misuse opportunities to grasp more power and money.
In DC their salaries are often absurdly high.