If breaking the law (by lying under oath) to conceal an affair was impeachable, why is breaking the law (by violating campaign-finance laws) to conceal an affair not impeachable?

If “cheating the electoral system” (by means of a burglary) was impeachable, why is cheating the electoral system (by means of illicit hush money) not impeachable?

If cheating “our institutions” (by means of an “assault” in “every way” on the legal system) is impeachable, why is cheating those institutions (by means of nonstop presidential mendacity and relentless attacks on the Justice Department and the F.B.I.) not impeachable?