Will she really take down a sitting president? Well, no, and if she did it would probably indicate a very divided and unpopular Democratic party. But if the media takes her campaign seriously (doubtful) I do think she can have a positive impact on the tone and content of politics. Cynicism has rotted our political system to the core and we need a human-centric vision of optimism and love paired with deep reforms to build a government that works for the well-being of everyone.
She also correctly rejects the idea that Putin is at all open to good faith negotiation yet, and implicitly the view of some progressives that the US should deal on Ukraine's behalf, whether they want it or not, with a genocidal regime that unilaterally threw out the last agreement as soon as military victory seemed to be within reach.