Investigations often damage the president's approval rating, particularly if the inquiry drags on for a long time. But that may not matter to a historically unpopular president like Trump.
As the impeachment inquiry gathers pace in the US, Donald Trump is likely to keep doubling down on his opponents.
AAP/EPA/Chris Kleponis
As the impeachment inquiry gathers pace, both sides seem to be digging in. What happens in the inquiry in the next few months will have a huge impact on the 2020 presidential election.
President Richard Nixon, left, and President Donald Trump, right.
AP//Frank C. Curtin; REUTERS/Jonathan Ernst
President Trump solicited foreign help for his presidential campaign. So did presidential candidate Richard Nixon. The difference, writes scholar Ken Hughes, is that Nixon was more skilled at it.
Volodymyr Zelensky: ready to make concessions.
Stepan Franko/EPA
Africa has already felt the effects of Donald Trump's climate change denialism. Recent events are also raising political issues of keen interest among the continent's democrats.
If he’s kicked out, could he come back?
AP Photo/Evan Vucci
A little-known provision of the Constitution might allow Trump to be reelected president in 2020 even if he is removed from office through the impeachment process.
Though the call between Trump and Morrison does not indicate any Australian government wrongdoing, it shows how the PM’s bromance with the president brings its political embarrassments.
Mick Tsikas/AAP
In many instances, whistleblowers find the abusive power they have revealed turned against them, both ending their careers and harming their personal lives.
Donald Trump and Rudy Giuliani in late November 2016, after Trump won the presidential election.
AP/Carolyn Kaster
A former congressional staffer says withholding damning evidence from Congress and using civilians to carry out presidential or intelligence agency agendas links the Ukraine crisis to other scandals.
The Founders saw impeachment as a regular part of ensuring presidential accountability. A constitutional scholar offers a possible process for a rapid and smooth impeachment inquiry.
Reporters ask Nancy Pelosi about the formal impeachment inquiry against Trump.
AP Photo/J. Scott Applewhite
As the House mounts an impeachment investigation of President Trump, examples from Central and South America show that ousting an executive leader from office doesn't always have the intended effect.
Participants in the Women’s March gather near the Lincoln Memorial in Washington in January 2018.
(AP Photo/Cliff Owen)
The United States is exhibiting several of the signs that have historically resulted in uprisings and revolutions. Is another American revolution looming?
Trump loves a street fight – one reason why Pelosi’s decision to initiate an impeachment inquiry is so risky.
Doug Mills/EPA
The conflict between Congress and President Trump over his dealings with Ukraine's president is just the latest version of a long-running struggle for power between the two branches of government.
Democrats are frustrated that Robert Mueller did not make a clear-cut case for impeaching President Donald Trump.
AAP/EPA/Jim Lo Scalzo
While some have seen Mueller's testimony as a disappointment, Democrats may still initiate impeachment proceedings against Donald Trump in the House of Representatives.
Mueller testifies before the House Intelligence Committee.
Reuters/Alex Brandon
To one scholar of the post-truth era, tuning in to Robert Mueller's testimony Wednesday was to hear a duel over the facts. Not what the facts imply – but what the facts are.