What happened
On June 17, 1972, burglars broke in to the office building of the Democratic National Committee at the Watergate Office Complex. These burglars were trying to get information and plans of the democratic party by tapping into phones and stealing classified papers and documents. Investigations showed that these burglars were tied to the reelection campaign of president Richard Nixon. After these burglars were caught, president Nixon did all he could to cover up the crime and try to not let the public get word about it. He tried to tell the FBI to cancel investigations of the burglary, raised "hush money" for the criminals, burning and disposing of evidence, and getting rid of staff who wouldn't help to cover the scandal up. It wasn't confirmed whether Nixon was involved with this burglary before it happened, but the fact that he tried to cover up for it was the reason the Nixon Administration got into trouble.
Nixon's resignation
It wasn't until 1974 when the scandal came to the public. As soon as Nixon was clear that people knew what had happened, and they wouldn't be happy with him, he resigned. President Gerald Ford was next to take office, and he pardoned Nixon for and crimes he "committed or may have committed" during his presidency.
long term effects
This incident changed how citizens thought about leadership, and they became more cautious about how they vote for presidents. Our expectations of trust for presidents is more strict now, and it is hard to live up to these expectations.