See the article and State Department testimony below, emphasis mine.
NYT, from 2013:
"Last summer, as the fighting in Syria raged and questions about the United States’ inaction grew, Secretary of State Hillary Rodham Clinton conferred privately with David H. Petraeus, the director of the C.I.A. The two officials were joining forces on a plan to arm the Syrian resistance.
The idea was to vet the rebel groups and train fighters, who would be supplied with weapons. The plan had risks, but it also offered the potential reward of creating Syrian allies with whom the United States could work, both during the conflict and ___after President Bashar al-Assad’s eventual removal___.
Mrs. Clinton and Mr. Petraeus presented the proposal to the White House, according to administration officials. But with the White House worried about the risks, and with President Obama in the midst of a re-election bid, they were rebuffed."
http://www.nytimes.com/2013/02/03/us/politics/in-behind-scen...
From 2011, testimony by Jeffrey Feltman, Assistant Secretary of State for Near Eastern Affairs, State Department:
"But we take the advent of the [Syrian National Council] very seriously, and we support the broader opposition’s efforts to focus on the critical task of expanding and consolidating its base of support within Syria by articulating a clear and common vision and ___developing a concrete and credible post-Assad transition plan.___"
http://www.foreign.senate.gov/imo/media/doc/Jeffrey_Feltman_...
At least to 2006, ten years ago, thanks to the US Embassy cable published by Wikileaks:
https://wikileaks.org/plusd/cables/06DAMASCUS5399_a.html
Some coverage:
http://america.aljazeera.com/opinions/2015/10/wikileaks-cabl...
"The cables also show that U.S. support for efforts to overthrow the Syrian government beginning in 2011 were not a response to the Assad government’s repression of protests but rather a continuation of a years-long strategy by more directly violent means."
Without that cable, this would be impossible to prove. Helps understanding why Manning who leaked that was 9 months in solitary confinement, stripped naked:
https://www.theguardian.com/world/2011/mar/11/stripped-naked...
Just a reminder, this is the presidential candidate in question:
Citation still needed. The material you provided is interesting and perhaps notable, and perhaps, if followed through, could be first steps in a campaign to remove Assad. But it's far from a direct call for regime change, as you are claiming.
Again, I'm probably more in agreement with your perspective than disagreement, but we all parties are best served if we make make more precise, evidence backed claims.
Hint: She and her husband are in bed with the House of Saud. Her (their) deep commitment to Israel is unquestionable. Never forget that she's a neocon and worships Henry Kissinger. It's just that she's joined at the waist to a democrat.