WASHINGTON – President Donald Trump wraps up the week-long Republican convention Thursday with a nomination acceptance speech that is already contentious because of its location: the White House.

Despite objections that the executive mansion should not be used for such an overt campaign event, Trump will make his prime-time argument for a second term from a makeshift outdoor theater on the South Lawn.

His likely goals: Defend his record and attack that of Democratic challenger Joe Biden.

“We have to win,” Trump told Republican delegates Monday after they voted to re-nominate him during a meeting in Charlotte. “This is the most important election in the history of our country.”

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Trump is accepting re-nomination amid the COVID-19 pandemic that has killed more than 179,000 Americans and put millions more out of work.

Democrats contend that holding a convention speech at the White House violates the Hatch Act, a law that prohibits federal employees from engaging in political activities on government property. Although Trump himself is not subject to the Hatch Act, Democrats say the preparations made by aides for the event and their participation in it are at odds with the law.

“The American people know these people are unethical and illegal and doing things outside the law,” said House Speaker Nancy Pelosi, D-Calif.

Using the White House for an event of this kind is not improper, Trump and other administration officials said. “The President is not subject to the Hatch Act and is free to engage in political activity at any time,” said a White House statement.

Nor is it unprecedented, they said; President Franklin D. Roosevelt was in the Executive Mansion in 1940 when he spoke via radio to the Democratic convention in Chicago that nominated him for a third term.

Trump’s White House speech will cap a fourth and final night of convention speeches by supporters who have praised Trump and sought to paint Democrats as a party of socialism and lawlessness. The Republicans scrambled to put together a virtual convention after canceling plans for more traditional activities in Charlotte, N.C., and Jacksonville, Fla.

Thursday’s program, including speeches by Republican lawmakers and Trump aides, is scheduled to start at 8:30 p.m. ET

Trump is expected to speak shortly after 10 p.m., and his speech will be followed by a fireworks display.

In defending their selection of the White House, Trump and aides said they had planned to hold a more traditional convention and acceptance speech in Charlotte, but had to change that because of the spread of COVID-19. A substitute plan for a Trump speech in Jacksonville also fell through because of the virus.

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Before announcing he would speak on the South Lawn of the White House, Trump said the presidential residence would be cheaper and easier to secure. In his remarks to delegates on Monday, Trump said he is looking forward to rallying his supporters during his White House speech.

“I have to tell you I think we have the greatest base of support anywhere at any time any election and people are starting to find that out,” Trump told his backers.

President Donald Trump speaks during a news briefing at the White House, Thursday, July 2, 2020, in Washington. (AP Photo/Evan Vucci)

During this week’s online convention, based mostly in Washington, planners played videos of Trump presiding over naturalization ceremony and issuing a pardon, with both events at the White House. First lady Melania Trump gave her convention speech from the recently renovated White House Rose Garden.

Secretary of State Mike Pompeo addressed the convention from Israel on Tuesday in a unique and much-criticized appearance by the nation’s top diplomat.

Another Cabinet member – Housing and Urban Development Secretary Ben Carson – is on Thursday’s speaking list, just before Trump’s acceptance speech.

The Thursday program also includes presidential daughter Ivanka Trump.

Congressional speakers include Senate Majority Leader Mitch McConnell, R-Ky.,and House Minority Leader Kevin McCarthy, R-Calif. Viewers will also hear from Rep. Jeff Van Drew, R-N.J., a former Democrat who switched parties during the president’s impeachment.

Non-government Trump supporters scheduled to speak include the widow of a slain retired police officer in Missouri, a businesswoman from Wisconsin, and the parents of a U.S. aid worker killed overseas by the Islamic State.

Then there is former New York City Mayor Rudy Giuliani, a defense attorney for Trump during impeachment as well as Special Counsel Robert Mueller’s investigation into Russia interference during the 2016 presidential campaign.

Trump has used the convention to essentially turn the White House into a political arm of the Republican Party, said Brian Fallon, a Justice Department spokesman during the Barack Obama administration. It is part of a pattern of disregarding standards that range from specious executive orders to threats to the Post Officeover mail-in voting, he said.

If people ignore this kind of thing, Fallon added, it doesn’t bode well if Trump decides to resist the results of the election should he lose to Biden.

“It does not inspire confidence about how our system will respond to Trump’s lawlessness in the context of an election he refuses to concede,” he said.