The president must be held accountable. No one is above the law.

US SPEAKER of the House Nancy Pelosi, Democrat of California, announces a formal impeachment inquiry of US President Donald Trump on Tuesday, in Washington, DC — the first step in a process that could ultimately lead to Trump’s removal from office. AFP

WASHINGTON (AFP) — The announcement Tuesday of a formal impeachment inquiry by the Democrats in the House of Representatives into President Donald Trump for abuse of power is a high-stakes gambit with uncertain consequences.

Nancy Pelosi, the Democratic speaker of the House, had shown little appetite for impeachment during the first three years of Trump’s tumultuous presidency.

But the political scandal over Trump’s attempt to seek dirt from Ukraine on his potential 2020 Democratic presidential rival Joe Biden was the last straw for the top Democrat in the House.

Pelosi said the six House committees already investigating Trump on various grounds would proceed with their probes under the umbrella of an official impeachment inquiry.

“The president must be held accountable,” Pelosi said. “No one is above the law.”

More than 150 of the 235 Democratic members of the 435-seat House have shown support for impeachment or the opening of an inquiry into removing the chief executive.

No House Republicans have come out in favor of impeachment and Republicans currently control the Senate, making conviction unlikely.

Trump tweeted that impeachment was “presidential harassment” and “witch hunt garbage.”

No president has been ousted from office by impeachment, but even the threat can bring one down — Richard Nixon resigned in 1974 to avoid certain removal in the Watergate scandal.

Two presidents beat the process: the House formally impeached Andrew Johnson in 1868 and Bill Clinton in 1998, but in both cases they were acquitted in the Senate.

If lawmakers believe a president is guilty of what the US Constitution calls “treason, bribery, or other high crimes and misdemeanors,” the process begins in the House of Representatives.

Any member can introduce an impeachment resolution which, like any other bill, is sent to a committee. The process can be also be started without a resolution, as with the current impeachment inquiry.

The committee can review the evidence it receives, or carry out an investigation itself.

If the evidence is strong enough, the committee crafts articles of impeachment — the political equivalent of criminal charges — and sends them to the full House.

The House can pass the articles by a simple majority vote, “impeaching” the president.

The articles then go to the Senate, where a trial takes place, with representatives from the House acting as prosecutors and the president and his attorneys presenting his defense.

The chief justice of the Supreme Court presides over the trial in the Senate.

The 100-member Senate then votes on the charges, with a two-thirds majority necessary to convict and remove the president.

If the president is convicted, the vice president then takes over the White House.