What's the Trump impeachment inquiry about? The White House is in damage limitation mode following a whistleblower complaint that revealed details about a phone call between President Trump and Ukraine's president, Volodymyr Zelensky. The whistleblower expressed an 'urgent concern' that Mr Trump had used his office to pressure a foreign power to damage a political rival and leading Democratic presidential candidate, Joe Biden.

Now the Democrats have launched a formal impeachment inquiry into what went on. Where might this end up and what does it mean for American politics?

David Aaronovitch is briefed on the wider context to this story and how the case will likely be built both for and against Donald Trump. He also asks how significant this moment is likely to be in US history?

GUESTS:

Josh Gerstein, Senior Legal Affairs Contributor, Politico

Producer: Serena Tarling