A simple guide to impeachment: What next for Trump?

US President Donald Trump has been impeached and now faces the next stage of a process that could, with enough support in Congress, see him removed from office.

It all centres on whether or not he improperly sought help from Ukraine to boost his chances of re-election in 2020.

Mr Trump became only the third president in US history to be impeached after two votes in the Democratic Party-controlled House of Representatives - but more on what that means below.

President Trump, who is a Republican, strongly denies any wrongdoing.

What is he accused of doing wrong?

President Trump is accused of pressuring Ukraine to dig up damaging information on one of his main Democratic challengers for the presidency in 2020, Joe Biden, and his son Hunter.

Hunter worked for a Ukrainian company when Joe Biden was US vice-president.

The president is accused of dangling two things as bargaining chips to Ukraine - withholding $400m of military aid to Ukraine that had already been allocated by Congress, and a White House meeting for Ukraine's president.

This, Democrats say, amounts to an abuse of presidential power, using the office for personal political gain and to the detriment of national security. Ukraine was using that money in its ongoing conflict with Russia.

Mr Trump is also accused of obstructing Congress by refusing to co-operate with the congressional inquiry.

What is the evidence against Trump?

A formal complaint from a whistleblower - an unnamed intelligence official who wrote a letter expressing concern about Mr Trump's 25 July call with President Volodymyr Zelensky - kicked off the impeachment process in early September.

A rough transcript of the call revealed that Mr Trump had urged President Zelensky to investigate discredited allegations against Joe and Hunter Biden.

The call came shortly after Mr Trump had blocked the release of millions of dollars in US military aid to Ukraine. A senior official later testified that the president made clear the release of the aid was conditional on Mr Biden being investigated, but the White House denies this.

In a series of public hearings, a procession of US officials have testified that there was a White House shadow foreign policy led by the president's personal lawyer, Rudy Giuliani.

Its aim was to get Ukraine to open an investigation into the Bidens and declare as much publicly.

What next?

Nothing is set in stone yet, but the general consensus is the Senate will start its trial perhaps as early as the second week in January when it returns from its winter recess.

That's what Chuck Schumer, the Democratic Senate minority leader, has requested.

And while Republican Senate leader Mitch McConnell may not like some of his counterpart's other requests for trial procedures, he may be OK with this timeline.

What is his defence?

Mr Trump denies using US military aid as a bargaining chip with Mr Zelensky and has repeatedly insisted his call with Ukraine's leader was "perfect".

He has called the impeachment inquiry a "witch hunt" by Democrats and elements of the media.

He also says it was appropriate to ask Ukraine to investigate "corruption", referring to the energy firm where Hunter Biden worked.

The Republican defence comes in three parts:

- Ukraine's president said he felt no pressure

- The Ukrainians were unaware the aid was held back

- US military aid was eventually released

What is impeachment anyway?

To impeach, in this context, means to bring charges in Congress that will form the basis for a trial.

The US constitution states a president "shall be removed from office on impeachment for, and conviction of, treason, bribery, or other high crimes or misdemeanours".

It's important to note this is a political process, rather than a criminal one.

What is the process?

It happens in two stages.

The first stage is done now - two articles of impeachment (charges) were brought to the House of Representatives and passed in a vote along party lines.

Next the process heads to the Senate where a trial will be held in January.

But here, a two-thirds vote is necessary for a president's removal - and this milestone has never been reached in US history.

The Senate is currently controlled by the Republican Party so conviction is considered unlikely in Trump's case.