LaRouche has a history of success using similar tactics involving Soros-related conspiracy theories. In 2003, he and his minions charged Soros with profiting from an international drug cartel (read here and here). During the 2004 presidential campaign, that charge was actually repeated by mainstream Republicans such as then Speaker of the House Rep. Dennis Hastert (read here), David Horowitz (read here) and Accuracy in Media (read here).
LaRouche has a long history of recklessly charging political figures with drug dealing -- most famously Henry Kissinger (read here) and Queen Elizabeth (read here). Those accusations were laughed out of the market of public opinion, for obvious reasons, but the Soros accusations seem to find more receptive ears. For years, Republican organizations such as the National Legal Policy Center have promoted a world view featuring Soros as Satan (read here), a trope readily picked up by Fox News. (Googling 'Soros +"Fox News"' gets 465,000 hits. He's their favorite target, and no charge seems too wild for them if Soros is in the story.)
So LaRouche may be calculating that this will be another way for him to sneak the camel's nose of extremism under the Republican tent. The Republicans should take care if they let that nose in. Pretty soon, the whole camel could follow.
Here's the rough draft of the conspiracy theory, with the LaRouchian paranoia still intact. Watch for cleaned-up versions in the Republican rumor mills. Some of his charges actually originated in the Republican blogs and media outlets, so his views may resonate there.
from LaRouche Political Action Committee: "How Soros Financed Obama's Campaign"
In late 2006, George Soros, the British empire/Wall Street gatekeeper of the Left, vetted Senator Barack Obama's potential Presidential candidacy on behalf of financier oligarchs. Soros then introduced Obama to a selected financier group, and Obama soon afterwards announced he would seek the White House.
By the way, in January, LaRouche was absolutely certain that Obama was a stalking horse for a Bloomberg presidential bid (read here: 'Obama Will Get Chopped Down To Prepare Bloomberg Run'), a certainty which he now seems to have forgotten.