Biden secured 3,558 delegates after the roll call vote on Tuesday, which took place at a largely virtual convention, which was nominally held in Milwaukee, Wisconsin. Candidates needed 1,991 delegates to win the presidential nominee for their party, a threshold Biden reached earlier on after Senator Bernie Sanders dropped out.

The second night of the four-day virtual Democratic National Convention was themed on leadership, especially on a global scale, and Democrats took the opportunity to criticize Trump's foreign policy.

Former Secretary of State John Kerry in his remarks said Trump is incapable of defending the country in contrast to Biden's steady hand.

"Joe understands that none of the issues of this world - not nuclear weapons, not the challenge of building back better after COVID, not terrorism and certainly not the climate crisis - none can be resolved without bringing nations together," Kerry said.

Kerry also said only Joe Biden can make "America lead like America again."

"This moment is a fight for the security of America and the world," the Obama administration's top diplomat added.

Former Secretary of State Colin Powell, who served under the George W. Bush administration, also made a case for supporting Biden.

"He will restore America’s leadership and our moral authority… and restore the alliances we need to address the dangers that threaten our nation from climate change to nuclear proliferation," Powell said.

Powell also said Biden will stand up to adversaries and trust US diplomats and the intelligence community.

US Senate Minority Leader Chuck Schumer said the United States needs a "steady" US president to pull the country out of its crisis.

Many of the Democrats throughout the night described Trump as selfish. Former acting Attorney General Sally Yates opened the night with a speech about Trump's alleged abuse of power.

"From the moment President Trump took office he's used his position to benefit himself rather than our country, he's trampled our rule of law," Yates said. "He treats our country like it's his family business, this time bankrupting our nation's moral authority at home and abroad."

Former President Bill Clinton slammed Trump for his mishandling of the US response to the domestic outbreak of the novel coronavirus disease (COVID-19) and his disagreement with advice from medical experts.

"COVID hit us much harder than it had to," Clinton said.

Former President Jimmy Carter said Biden is the right person to lead the United States under the current challenges it faces.

The Democrats' presumptive vice presidential nominee, Senator Kamala Harris, will be the keynote speaker on Wednesday, the night before Biden delivers his nomination acceptance speech from Delaware.

The Republican National Convention is scheduled to take place August 21-24 at Charlotte, North Carolina. Trump said he will deliver his acceptance speech from the White House lawn.

Biden is ahead nationally in the most recent ten polls posted on realclearpolitics.com by an average of about 7 percent. The same site also shows Biden leading in the largest battleground states including Florida, Pennsylvania, Ohio and Michigan.