(CNN) Hillary Clinton is finding her political footing.

In the space of a week, the presumptive Democratic nominee delivered a sober national security speech addressing the worst mass shooting in American history; won the resounding endorsement of the sitting commander in chief; and castigated Donald Trump as a "loose cannon" better suited for reality television than the Situation Room.

The massacre at an Orlando gay club that killed 49 people early Sunday thrust national security and terrorism to the forefront of the 2016 presidential campaign, just days after Clinton clinched her party's nomination for the White House last week. The horrific event -- the worst terrorist attack since 9/11 -- offered Clinton the chance to make a powerful case for her foreign policy experience, and ample opportunity to deliver scathing criticism of her rival.

In back-to-back speeches on Monday and Tuesday, Clinton unleashed blistering rebukes of Trump's candidacy. Pointing to his response to the Orlando tragedy -- in particular, his renewed calls to temporarily ban Muslims and other migrants from entering the United States -- Clinton slammed Trump as "temperamentally unfit" and "totally unqualified" to be leader of the free world.

"It was one thing when he was a reality TV personality -- you know, raising his arms and yelling, 'You're fired,'" Clinton said at a campaign rally in Pittsburgh Tuesday afternoon. "It is another thing altogether when he's the Republican Party's presumptive nominee for president."

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