First of all, in the opening crawl, it's stated that "With the support of the Republic, General Leia Organa leads a brave Resistance."
That seems to be contradicted by everything else we're told about the relationship between the Republic and the Resistance, but there you go...
According to the novelization (as filtered through this daily dot article, but hopefully someone who's read the book can back me up) Leia had just sent an envoy, Korr Sella, to petition the Senate on behalf of the Resistance.
She was the Resistance's hope for aid from the Republic Fleet, so since she perished on Hosnian Prime (visible in the balcony shot) and the fleet was destroyed (visible in the long shot of the planets exploding), that would motivate the comment you referenced in the question.
2) There's someone important on that Republic Senate balcony
Just before Starkiller Base destroys the Hosnian System—including Hosnian Prime, the capital of the Republic—the camera pushes in on a balcony full of well-dressed people, including a young black woman in a uniform. Although the movie doesn't explain who that is, the novelization reveals that the character, played by Maisie Richardson-Sellers, is Korr Sella, General Leia Organa's envoy to the Senate.
Before the discovery of Starkiller Base, Leia, the head of the Resistance, sends Sella to petition the Republic for help in the fight against the First Order. Leia can't go herself, she tells Sella, because the Republic capital world isn't safe for a political pariah like her. (The Republic, which signed a treaty with the First Order after Return of the Jedi, publicly disavows the Resistance's unsanctioned conflict with it.)
"I would have a terrible 'accident,' or become the victim of some 'deranged' radical," Leia says. "Or I would eat something that didn’t agree with me. Or encounter someone who didn’t agree with me."