Video report by ITV News US Correspondent Emma Murphy
Donald Trump's second impeachment trial will go ahead after senators voted it was constitutionally permissible to prosecute the former US president.
56 senators voted in favour of the impeachment trail going ahead, while 44 voted against - rejecting an attempt by Mr Trump's defence team and some Republican allies to halt the trial because he is no longer in office.
The former US president is charged with inciting the deadly mob attack on the Capitol on January 6 to overturn the election.
Video report by ITV News Correspondent Robert Moore focuses on reactions from Floridians as Donald Trump's impeachment trial begins
But Mr Trump's lawyers are insisting he is not guilty of incitement of insurrection and that his words encouraging a crowd to "fight like hell" for his presidency were just a figure of speech.
Five people died during the US Capitol riots on January 6, including a woman shot by police inside the building and a police officer who died the next day of his injuries. Rioters stormed the building, which is the meeting place of the Congress, to try to stop the the certification of Joe Biden's victory.
During the opening of Trump's impeachment trial, a congressman recalled the day of the Capitol riots when his daughter and son-in-law "thought they were going to die".
Rep. Jamie Raskin, the lead House impeachment manager, gave an emotional account of the US Capitol attack
Rep. Jamie Raskin, the lead House impeachment manager, gave an emotional account of his experience on the day. He had been joined by members of his family, the day after he had buried his son, who took his own life in December.
His daughter and son-in-law were in the Capitol and hid under a desk, where they sent what they thought were their final texts. He says: “They thought they were going to die.”
Separated from them in the House chamber, Raskin described people around him calling to say goodbye to their families, members removing their congressional pins to try to evade detection.
He said he heard the rioters “pounding on the door like a battering ram. The most haunting sound I ever heard. And I will never forget it".
He choked up as he recalled his daughter telling him she never wanted to return to the Capitol again.
Through tears, Raskin says: “This cannot be the future of America.”
Mr Trump is the first president to be impeached twice and the first to be impeached after leaving office.
Trump’s defence team argued it was unconstitutional to prosecute a former president.
ITV News US Correspondent Emma Murphy commenting on the opening of Trump's impeachment trial
But the House prosecutors cited the nation’s founders to declare a president “must answer comprehensively for his conduct in office from his first day in office through his last.”
There is no “January exception” just before he leaves office, prosecutors argued.
The chamber is divided 50-50 between Democrats and Republicans, with a two-thirds vote, 67 senators, required for conviction.
The opening arguments are scheduled to begin on Wednesday, with up to 16 hours per side for presentations.
Then there are hours for deliberations, witnesses and closing arguments. The trial is expected to continue into the weekend and next week.