US President Donald Trump has warned his Democratic challenger Joe Biden will "demolish" the American dream if he wins the White House in November.
Speaking on the final night of the Republican convention, the president depicted his opponent as "the destroyer of American greatness".
He said the Democrats would unleash "violent anarchists" upon US cities.
Mr Biden has a steady single-digit lead in opinion polls over Mr Trump with 68 days until voters return their verdict.
The end of the Republican convention heralds a 10-week sprint to election day, and the coming campaign is widely expected to be one of the ugliest in living memory.
On Thursday night, the president asked voters for another four years in office, vowing to dispel the coronavirus pandemic that has ravaged the US economy and quell civil strife ignited by police killings of African Americans.
Trump accepted his party's renomination from the South Lawn of the White House.
"This election will decide whether we save the American dream," he said, "or whether we allow a socialist agenda to demolish our cherished destiny."
He added: "Your vote will decide whether we protect law-abiding Americans, or whether we give free rein to violent anarchists, agitators and criminals who threaten our citizens."
The president said the Democrats at their party convention last week had disparaged America as a place of racial, social and economic injustice.
"So tonight," he added, "I ask you a very simple question - how can the Democrat party ask to lead our country when it spends so much time tearing down our country?
"In the left's backward view, they do not see America as the most free, just and exceptional nation on earth. Instead, they see a wicked nation that must be punished for its sins."
In a blistering attack on his opponent's decades-long political life, he continued: "Joe Biden spent his entire career outsourcing the dreams of American workers, offshoring their jobs, opening their borders and sending their sons and daughters to fight in endless foreign wars."
While Mr Trump portrayed his challenger as "a Trojan horse for socialism", Mr Biden's lengthy record as a political moderate was a hindrance for him as he competed to capture his party's nomination.
Mr Trump mentioned Mr Biden more than 40 times; the Democrat did not once name Mr Trump in his speech last week, though criticism of the president permeated Mr Biden's remarks.-BBC