They're at the heart of two of the most heated current debates now before Congress — on restricting gun ownership and raising the government's borrowing ceiling to pay current bills.
President Barack Obama is considering ways to circumvent Congress on one — but not the other.
He is expected to unveil a comprehensive gun-control package as early as Wednesday. It's expected to include controversial proposals to ban assault weapons, increase background checks and limit the capacity of ammunition magazines.
But he's also expected to outline 19 other steps on guns he plans to take by executive action alone, bypassing Congress.
The Second Amendment protecting an individual's right to possess and carry firearms was adopted on December 15, 1791.
Meanwhile, Obama is resisting suggestions by many Democrats and some constitutional scholars to act on his own to bypass and challenge the present, congressionally set limit on the government's borrowing authority.
They cite the 14th Amendment, ratified July 28, 1868, which holds that the "public debt" cannot be questioned.
Although that provision was originally meant to ensure payment of Union debts after the Civil War, those advocating its use in the current debate are challenging the constitutionality of congressional efforts to limit borrowing to pay bills.
Obama's not buying into that argument — and says Congress must act to raise the congressionally set $16.4-trillion debt ceiling. If that ceiling is not raised by sometime in February or early March, the government will not be able to pay all its bills.
"America cannot afford another debate with this Congress about whether or not they should pay the bills they've already racked up," he said.