Let’s say there are two political parties in a country. The Evil Party and the Stupid Party. When the Evil Party’s candidate is elected president, he abuses his power and rules by diktat, like an all-powerful king. That’s why he’s evil. Not everyone likes this, however. Some don’t like his diktats, and some don’t like kings. The latter complain that this is contrary to the country’s constitution, but in fact no one is going to stop the Evil president from abusing his power while he’s in office.
One of the Evil president’s chief goals is to ensure that the Stupid Party never wins a presidential election. But now let’s suppose (hey, it’s just a hypothetical) that the Stupid Party wins a presidential election one year. At this point the Party has a choice. The Stupid president can either assume the broad king-like powers of an Evil president, or he can rule more modestly in what he thinks is the country’s constitutional tradition.