The impeachment investigation of US president Donald Trump has formally started, but much has changed since 1974, when Richard Nixon was forced out of office.
Senate Majority Leader Mitch McConnell is known as a master of Senate rules. If the House impeaches President Trump, what could he do to influence the process – and outcome – of a trial?
Members of Congress factor what the public thinks into their decisions. But it's difficult to measure what the public is really thinking.
Are Republican leaders overestimating the extent to which the public wants them to defend Donald Trump?
Meanwhile, the polls indicated that support for impeachment has shifted markedly, with most Americans now supporting it.
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, 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 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.
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.
In many instances, whistleblowers find the abusive power they have revealed turned against them, both ending their careers and harming their personal lives.
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.
How Ukraine has reacted to controversy over a phone call between its President Volodymyr Zelenskiy and Donald Trump.
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.
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.
With the House of Representatives taking the unusual approach of censuring a sitting president, attention will now turn to next week's testimony by Robert Mueller.
Those who want President Trump out of office should forget about the 25th Amendment; it won’t work as they hope or believe. The amendment is a complex law that – by design – is very hard to use.
Politics have pervaded the debate about whether Congress should impeach President Trump. One legal scholar says that whether to impeach – or not – should not be viewed as a political question.
Many were confident the US Constitution was robust enough to check Donald Trump's worst excesses, but the real push back has come from elsewhere.
President Trump has invoked executive privilege to stymie congressional investigators. Another president, Richard Nixon, did the same thing. It helped Nixon hold onto power – but only for a while.
How can a community decide the direction it should go, if its members cannot even agree on where they are? Two political scientists say the growing phenomenon of dueling facts threatens democracy.