Before Occupy D.C. protesters swarmed the Washington Convention Center on Friday night, Mayor Rudy Giuliani delivered a speech to the free market faithful at the Americans for Prosperity conference. In his speech, he made the case that Barack Obama is responsible for the Occupy protests because of his class warfare rhetoric, his demonization of American business leaders (or more specifically those who don't support his campaigns), and his rhetorical support for the increasingly violent movement has given aid and comfort to the mob. Giuliani also made the case that this mob may take down the Obama presidency.
You can see those comments in the video below, followed by events that took place outside the convention center later that night, when protesters attacked AFP members as they tried to leave the building, injuring several of them (including an 78-year-old woman who was pushed down the stairs and had to go to the hospital for her injuries), barricaded the doors to the convention center, and blocked traffic on the streets—keeping law-abiding citizens with jobs from getting where they needed to be, some of whom can be seen in the video below confronting the protesters. According to the Washington Post, the protesters were also provoking violent altercations with neighborhood's residents throughout the night. And the whole time, the chant mob chanted: "This is what democracy looks like."
One other note on this protest: While Obama, Democrats, and the liberal media have indeed cheered on Occupy Wall Street, the protesters have been mostly independent of the "professional left." However, those lines are being increasingly blurred. This particular protest was organized by Health Care for Americans Now, a group that has received at least $5 million in funding from George Soros, and $25 million from the Atlantic Philanthropies, a foundation based in Bermuda that has funneled millions of dollars of foreign money into the American electoral system through a quirk in American tax laws that allows Bermudans to contribute to 501(c)(3) and 501(c)(4) organizations which are otherwise barred from accepting foreign funds. Health Care for Americans Now has deep ties to the Obama administration as well. So here you have a Soros-funded group, supplemented by foreign money, organizing an Occupy protest that nearly turned into a riot. And presumably it will take a riot for Democrats and the press to wake up to the threat these protests pose to the communities they've occupied.