History
Checks and Balances in Government
Quick fact
The U.S. Constitution deliberately gave each branch of government—congress, the president, and the courts—the power to block the others. For example, the president has a veto, but Congress can override that veto with a two-thirds majority, and the Supreme Court can later strike down the resulting law as unconstitutional.
Why this is interesting
How can a government be strong enough to lead, yet not so strong that it can tyrannize its citizens? The answer lies in a system where every branch holds just enough power to block the others.