(CNN) The US has grown more divided along partisan lines over the last two decades and past polling suggests the current impeachment inquiry into President Donald Trump is likely to only exacerbate those growing divisions.
Polling shows that the US is as divided on party lines as it's ever been -- and the start of that trend can be tracked back to the last impeachment crisis in the late 1990's involving then-President Bill Clinton. But that impeachment, and the impeachment inquiry into President Richard Nixon, took place at a time when the parties were far closer together.
Last month, House Speaker Nancy Pelosi opened an impeachment inquiry centering around Trump's phone call with Ukrainian President Volodymyr Zelensky after a whistleblower filed a complaint about the call. A transcript of the conversation released by the White House shows Trump repeatedly pushed Zelensky to investigate former Vice President Joe Biden and his son, Hunter. There is no evidence of wrongdoing by either Joe or Hunter Biden.
It's the first impeachment inquiry since Clinton was impeached by the House and then acquitted by the Senate, but the backdrop of Clinton's impeachment was a country that was far less divided on partisan lines than it is now. America is about as divided on party lines as it has ever been and the view going forward isn't rosy. Only 6% of Americans think the divisions will decrease, and the divisions aren't just skin-deep. Almost three-quarters said that Republican and Democratic voters not only disagree on plans and policies, but they disagree on even basic facts (including 77% of Republicans and 72% of Democrats), according to the recent Pew poll.
In 1997, about a year before Clinton was impeached, 22% said there was a great deal of difference between the parties. Now, over half of Americans believe there is a big difference between what the Democratic and Republican parties stand for, according to a Pew Research Center survey.
On October 8, 1998, the US House of Representatives voted to begin an impeachment inquiry into Clinton. In between late 1998 and early 1999, the number of people who saw a larger divide between Democrats and Republicans spiked. Since then, more and more people have said they've seen the gap between Democrats and Republicans growing, with the biggest jump -- 9 percentage points -- coming between 2015 and 2019. That increase came during the contentious 2016 presidential campaign and into Trump's presidency, as he's become one of the most divisive political figures in the country.
Other polling questions also show an increase in the perceived partisan divide. In a March 1996 survey from Gallup/CNN/USA Today, 30% said that most Democrats in Congress hold views that are too extreme and 40% said the same of Republicans. A similar question asked in Pew's 2019 survey found significantly more -- 61% of Americans -- said the Democratic Party is too extreme in its positions, while 63% said the same of the Republican Party.
And, according to the 2019 Pew poll, 78% of Americans said divisions between Republicans and Democrats are increasing.
Americans are also more divided around whether Trump should be impeached than they were at the time of either Clinton or Nixon's impeachment inquiries.
In a recent Gallup poll, 52% said that Trump should be impeached and removed from office -- up from June of this year and in line with multiple other national polls showing a very slight majority support for the impeachment inquiry.
During the impeachment inquiries into Clinton and Nixon, that split wasn't as pronounced as polling found most people were against impeachment.
The last Gallup poll before Clinton was impeached, conducted in October 1998, found 32% of Americans said that he should be impeached and removed from office, the second highest support of his removal since June of that year.
Support for impeaching Nixon, who faced impeachment proceedings in 1974 and eventually resigned, was slightly higher in Gallup's polling, but there was never a plurality who thought he should be removed from office. In February 1974, 38% of Americans said Nixon should be impeached and compelled to leave the presidency -- the highest it had been since they started asking the question in June 1973.
Support for impeaching Trump is also heavily split on partisan lines, especially as compared to Nixon.
Far more Democrats support Trump's impeachment now than did for Nixon in July 1974. At that point 71% said Nixon should be impeached, compared to 90% of Democrats who want Trump impeached now. Support for impeaching Trump among Republicans is much lower than it was for Nixon -- currently only 6% of Republicans want Trump to be impeached and 31% felt the same about Nixon. Independents showed about the same support for Trump being impeached as they did for Nixon.
The final impeachment poll regarding Clinton from Gallup in October 1998 found 58% of Republicans said Clinton should be impeached, and 29% of independents and 15% of Democrats agreed. Republicans supported impeachment significantly less than Democrats did, or do, for either Nixon or Trump. But more of Nixon's base supported impeachment (31% among Republicans), than Clinton's (15% among Democrats), or Trump's (6% among Republicans).