Complex sentence: A vote to increase the Debt Ceiling has usually been (post 1950s onward) a "legal budgetary formality" by the Presidency and the US Congress, not a political issue that would make the elected government fail to pass a yearly Budget.
Split into simpler sentences: A vote to increase the Debt Ceiling has usually been (post 1950s onward) a "legal budgetary formality" dealt with by the Presidency and the US Congress. The Debt Ceiling has not historically been a political issue that would make the elected government fail to pass a yearly Budget.