WASHINGTON, D.C. -- Nixon, Clinton, and now Trump.

For the third time in decades, Washington is in the throes of an impeachment proceeding.

What impact have these three different episodes had on public trust and the public psyche?

Consider Watergate.

Public trust in institutions was already waning at the time in part due to the Vietnam War, says Mark Rom, an associate professor at Georgetown University.

But, he says, the Nixon administration scandal had an additional impact, especially with older voters.

“I think many of the greatest generation believed that the government was truthful, believed that politicians were basically honest,” he said. “To learn that the president was lying and subverting the Constitution, trying to rig democracy in his favor - that was a real blow, especially to the older generation.”

Fast-forward to the 1990s and the Clinton impeachment. American University Prof. W. Joseph Campbell says the mounting partisan acrimony at the time is still felt today.

“That left a residue of hostility. It left a residue of anger,” Campbell said.

So, what impact will the Trump impeachment have? That is hard to tell. Experts say in a divided time such as this, many will view the any result through a partisan lens. Others are not tuning into the Senate trial at all.

“It’s not a topic that’s gripping the country or a suspenseful topic, as the Nixon impeachment proceedings were,” Campbell said.

Meanwhile, Rom argues that the multiple impeachment episodes in recent history could have a cumulative effect on public trust and confidence.

“There’s the mounting view that our system is corrupt and our politicians are corrupt,” Rom said. “The more often this happens - the more cynicism - the more the distrust of government is likely to grow and persist.”