Can America ever truly pay for its sins?

[Spongebob]

that's why the U.S army got defeated in Vietnam, then Afghanistan,

U.S army did not get defeated in Afghanistan, but moderate Muslims were defeated by the fundamentalist Muslims.

It is true that the US Army didn't lose in Afghanistan, but I think it's also true the the US lost the war overall.  The Taliban was not destroyed.  Al Qaeda was not destroyed.  What's left of a democratic government there won't likely be around much longer.  Given a decade or so, the country won't be much better off than when we entered entered the stage.  We did manage to destroy the terrorist training camps and improve society for women and others, but without a constant US presence that won't last.  We won most of the battles but lost the war.