IMO, the bigger and most immediate threat to liberal democracies is likely
global Peak Oil, which many unbiased analysts suggest either occured in 2008 at around 86 million barrels a day (m/b/d), or will occur by 2012 or 2015, topping at around 90 m/b/d before going into permanent decline.
Afterall, global oil production has essentailly been on a plateau since mid-2005, vacilating +/- 1.5 million barrels a day. Despite a four-fold increase in price from 2003-2008 - there was no appreciable increase in oil production from Saudi Arabia and other OPEC prioducers. That should tell us something.
Hence, I suspect that diminshing hydrocarbons on a glaobal basis, year after year, with its attending macroeconomic, geopolitical, and societal/psychological effects, could facilitate the rise of authoritarian and militarisitic leaders in some of today's "liberal democracies" (think G.W. Bush and Dick Cheney, but on steriods...) The EU seems to be slowly acknowleding this issue, for example:
http://www.reuters.com/article/idUSBRU01112520101110
Global oil availability has peaked -EU energy chief
BRUSSELS | Wed Nov 10, 2010 6:11am EST
BRUSSELS Nov 10 (Reuters) - The availability of oil worldwide has already peaked, the European Union's energy chief Guenther Oettinger said on Wednesday.
"My fear is that the global consumption of oil is going to increase, but European oil consumption has already reached its peak. The amount of oil available globally, I think, has already peaked," Oettinger told a news briefing in Brussels.
He was presenting a new EU energy strategy for investing 1 trillion euros over the next decade in a common EU energy network, to curb the bloc's dependence on fossil fuel imports.
..unfortuantely I didn't hear Obama call for similar measures in last night's SOTU speach. Another tragic missed opportunity.