Trump's impeachment is worth celebrating due to the sovereignty of our constitution and the rule of law being reaffirmed. The participation in our democracy, by Republicans and Democrat alike, from which impeachment resulted is what gives me reason to be optimistic.
Trump's impeachment is a poignant reminder that voting matters, as the oversight which lead to impeachment was only made possible by the House coming under Democratic control as a result of the 2018 midterm elections.
However, celebration of Trump's impeachment should be tempered with the acknowledgement that it never should've needed to come to this. Trump’s campaign and administration have been an undemocratic, malevolent, and incompetent edifice of lies, and one that - until impeachment - plowed undeterred through other protections designed by the founders to contain both despots and the tyranny of factions they are prone to create.
Most importantly, the edifice of lies that is Trump is still supported by 35-40% of the U.S. electorate. (While that is certainly better than a majority of the electorate supporting Trump, it is a significant amount of the U.S. populace). This remains a legitimate reason to be concerned about the well-being of our republic and our societal discourse.
The takeaway = impeachment is a short term victory, but the struggle to keep our republic goes on.