This grew to be inconvenient right around World War I, so to give the federal government more flexibility, Congress decided to set an aggregate borrowing limit known as the debt ceiling, which capped the total number of bonds that could be issued.

FORBES: How the Debt Ceiling can Affect Your Credit Card Statement

It may be that after the Supreme Court decides theMcCutcheon case, involving aggregate contribution limitations, that the standards for judging the constitutionality of contribution limit laws could change, making those laws harder to sustain.

FORBES: Supreme Court Rejects Case Challenging Corporate Political Donations