Hillary Clinton walks to her motorcade after landing in Tampa on Tuesday. (Melina Mara/The Washington Post)

TAMPA — On the eve of a “commander-in-chief forum,” Hillary Clinton used an appearance here to mock Donald Trump's national security credentials and tout her own experience as secretary of state and as a U.S. senator representing New York.

The Democratic candidate said the Republican nominee often has “no clue” as to what he’s talking about on military issues, pointing to statements he’s made about fighting the Islamic State terrorist group that Clinton said “have been all over the map.”

“He says he has a secret plan to defeat ISIS, but the secret is he has no plan,” Clinton told a crowd estimated at 1,500 at the University of South Florida, located in a community with sizable active-duty and military veteran populations. ISIS is another name for the Islamic State.

Speaking to reporters aboard her plane Sept. 5, Democratic presidential candidate Hillary Clinton said she's "taken aback" by revelations about Donald Trump's foundation's gift to a political group connected to Florida Attorney General Pam Bondi. (Video: The Washington Post/Photo: Melina Mara)

Clinton also accused Trump’s company of having fired military veterans because they had to take time off to fulfill military obligations, and she recounted Trump’s verbal back-and-forth with a Virginia family who lost a son in Iraq.

“His whole campaign has been one long insult to all those who’ve worn the uniform,” Clinton.

Her posturing came a day ahead of a forum in New York at which Clinton and Trump are scheduled to appear back-to-back on MSNBC and NBC to discuss issues that will confront the country’s next commander-in-chief.

A fired-up Joe Biden joined Democratic vice presidential nominee Tim Kaine at a Pittsburgh rally on Sept. 5. Speaking about Republican presidential nominee Donald Trump, Kaine said, "He thinks we're chumps." (Reuters)

Clinton’s appearance here also came on the same day that her running mate, Sen. Tim Kaine of Virginia, delivered a speech on national security in North Carolina, and Trump unveiled a list of nearly 90 military figures who are supporting him.

Speaking to reporters aboard her plane en route to Tampa, Clinton downplayed that number, saying previous Republican candidates have claimed far more support from the military.

Here at the rally, Clinton also recounted her work as a senator representing New York after the Sept. 11, 2001, attacks, as well as her role as secretary of state in the 2011 killing of Osama bin Laden by U.S. Navy SEALs.

“I was one who said I thought it was worth the risk,” Clinton said as she recounted being among those in the Situation Room with President Obama during her tenure as secretary of state.

“You go girl!” yelled a member of the audience.