WASHINGTON - Ninety-nine days after taking office, President Donald Trump on Friday is set to address the National Rifle Association, the hugely powerful US gun lobby that will surely give him a triumphant welcome.

The event will be heavy with symbolism.

Republican candidates jostling to the doors of the organization that prides itself on its ability to influence local and national elections may be a common sight. However, a sitting president addressing the group's members is far less so, the last time dating back nearly 35 years to Ronald Reagan.

This time, Trump will address the NRA's 146th annual convention in Atlanta, Georgia, where more than 80,000 members and some 800 exhibitors are expected to take part in a four day event.

The organization backed the real estate billionaire early in the 2016 presidential campaign and gave him significant financial support.

In a short video about the speech, the NRA draws a parallel between Trump's address and Reagan's -- evidence, if any were necessary, of the lobbying group's close ties to the 45th president.

"NRA members and gun owners helped put President Trump over the top," NRA Wayne CEO LaPierre said.

The organization has since given the president high marks, especially for his appointment of conservative judge Neil Gorsuch to the Supreme Court.

    - Campaign style -

In 1983 Reagan electrified NRA members gathered in Phoenix, Arizona during his re-election campaign.

"We will never disarm any American who seeks to protect his or her family from fear and harm," said the president, who has become an all-but sacred icon for many Republicans.

"The constitution says 'The right of the people to keep and bear arms shall not be infringed,'" Reagan added to thunderous applause.

The former actor was careful to cite the constitution's Second Amendment verbatim -- but only part of it.

The full sentence stipulates that "A well regulated militia being necessary to the security of a free state, the right of the people to keep and bear arms shall not be infringed."

That formulation has prompted many different interpretations depending on views and politics.

Although no elected official today advocates confiscating Americans' firearms, Democrats disagree with Republicans over the degree of regulation needed for weapons sales and permits.

Former president Barack Obama failed to overcome fierce Republican resistance when he tried to pass minor gun control legislation following the Sandy Hook School massacre that killed 26 people in 2012. Obama was angry at what he called an "epidemic" of US gun violence.

Trump was welcomed with wild enthusiasm when, in May 2016 while campaigning for president, he spoke NRA's national convention meeting in Louisville, Kentucky.

"Crooked Hillary Clinton is the most anti-gun, anti-Second Amendment candidate ever to run for office," Trump told the convention about his Democratic White House rival.

Eager to galvanize his base after humiliating setbacks in Congress, the president on Friday is expected to return to the campaign style of his 2016 NRA speech.

Then on Saturday Trump will travel to Harrisburg, Pennsylvania to tout his achievements at a rally of supporters.

Pennsylvania is one of three swing states -- including Michigan and Wisconsin -- that proved crucial for Trump's surprise victory in November, thanks in no small part to support from the millions of NRA members.-AFP