Five people arrested in Britain under terrorism laws in connection with an alleged plot to target the G20 summit in London this week advanced concerns among counterterrorists (CT) about militant organizations that have advocated violence during the many scheduled protests of the summit. Law enforcement agencies have put in place unprecedented security throughout the London area in anticipation of possible violence and terrorist attacks.

The arrests didn't surprise law enforcement and CT officials in the US and throughout Europe who have been on alert to not only Islamist jihadist terrorist attacks designed to take advantage of the world’s weakened economies, but also to potential terrorism by ideologically driven extremist, anti-capitalist groups against government officials and private sector business executives they blame for the world's financial mess.

Comprised of mostly anti-capitalist Marxists and anarchists, these 60s and 70s-style militant organizations’ rank and file have been reinspired by the global economic meltdown and are finding that the crisis not only is a successful recruiting tool, but that unsolicited membership is growing among the disenfranchised working class the world over. What concerns counterterrorists is the anti-capitalist violence that some leaders of these groups are openly promoting.

Counterterrorists have long been concerned about the potential for terrorism arising from discontented and disenfranchised populations. The CIA discussed this in an intelligence estimate several years ago.

In the US, CT officials say they are seeing signs that white and black supremacist groups are respectively manipulating typically poor and lower middle class frustrations, and are working to incite potentially violent anger towards a perceived bourgeoisie elite - the Wall Street-type financiers behind America's worrisome economic spiral downwards.

HSToday.us reported more than a month ago that US law enforcement and intelligence officials are concerned over a “significant up tick” in intelligence indicating that white supremacist groups and individuals espousing extremist “anti-government,” anti-wealthy sentiment is surging in the wake of the nation’s deteriorating economy that they blame on the federal government and wealthy bankers and mortgage lenders.

Conversely, though, authorities also are concerned about several avowed black Marxist-socialist groups that were born from militant black nationalist organizations of the 60s and 70s that also have been involved in violence and openly promoted a revolutionary call to arms against capitalist, "colonial" governments.

It's not a localized ideology. Brazil’s President, Luiz Inácio Lula da Silva, openly blamed the global economic crisis on “white people with blue eyes," saying it's wrong that black and indigenous people should pay for white people’s mistakes, according to Financial Times.

America’s - and the world's, for that matter - economic malaise clearly has made Western nations especially vulnerable to debilitating catastrophic terrorist attacks by anyone - be it Al Qaeda or anti-capitalist anarchists who'd like to see a complete collapse of "empirialist" powers.

Director of National Intelligence (DNI) Dennis C. Blair told the Senate Select Committee on Intelligence in early February that the consensus analysis of the “Annual Threat Assessment of the Intelligence Community” is that “the primary near-term security concern of the United States is the global economic crisis and its geopolitical implications.”

While the Intelligence Community’s (IC) warning that the threat the global economic rendering poses to US interests was couched in terms of other nations’ failing economies leading to failed states that could create vacuums for violence and extremism that could spill across national borders, America’s economic meltdown also makes the nation much more vulnerable to catastrophic attacks and homegrown terrorism by individuals angered over government and Wall Street’s role in the economic crisis. An anger that’s mirrored throughout Europe.

A week before Blair’s testimony, HSToday.us reported that counterterrorists are concerned that the US’s destabilized economy may have created a big enough vulnerability that terrorists could carry out a catastrophic attack that would financially cripple the nation – which has long been a stated goal of Al Qaeda and, more recently, violence promoting anti-capitalism groups.

British intelligence warned this month that a WMD attack on a British city is now more likely than it's ever been. On the heels of the warning, Home Secretary Jacqui Smith said this week's G20 meeting is a prime target for terrorists. CT authorities certainly are preparing for potentially violent anti-capitalist protests in London by groups that have publicly condoned the use of violence to protest the global economic crisis they blame on capitalism.

Dr. Dov Zakheim, former Under Secretary of Defense, told the House Committee on Armed Services this month that the global economic crisis holds the potential to “prompt even more hostile behavior on the part of nations such as Iran and Venezuela that already bear deep antipathy toward the United States,” and “could further destabilize states that are already vulnerable to internal unrest.”

“Finally, it could spur further international criminal behavior that could undermine internal American stability,” Zakheim said.

Given that Al Qaeda and affiliated terrorist groups desire to strike at America’s economic foundation, a catastrophic attack or attacks anytime soon could send the nation into an unparalleled financial tailspin that would be very difficult to recover from, government officials told HSToday.us.

“And Al Qaeda has to be looking at this as an opportunity … looking at every which way they can [to] possibly pull off a spectacular attack,” one of the officials said.

"We have set the stage for a catastrophe," James Rickards, a financial consultant at Omnis Inc. which provides security research for the Pentagon and IC, told the Associated Press in late February.

Given the world’s chaotic economic instability, CT authorities are concerned that not only the Al Qaedas of the world, but anti-capitalist anarachists might try to strike a death blow against the West through a spectacular attack designed to further weaken weakened Western economies.

The US is especially susceptible to an attack right now because Wall Street is so shaky, analysts said. The federal government would be hard pressed today to pump more money into an economy further decimated by a major terrorist attack.

At a March 11 House Committee on Armed Services hearing on the security challenges arising from the global financial crisis, chairman Ike Skelton (D-MO) warned that “we face a world that has been suddenly transformed, and not for the better. The governments of Iceland and Latvia have fallen as a result of the crisis, and others are likely to follow. Three of our most important partners in the Muslim world, Turkey, Indonesia and Pakistan, all face acute balance-of-payments."

“At a minimum, the global financial crisis will exacerbate an already growing set of political and economic challenges facing the world,” Skelton said, adding, “in country after country, the crisis is increasing citizen discontent and anger toward their leaders and providing an excuse for authoritarian regimes to consolidate their power.”

CT and law enforcement authorities have begun to brace for a resurgence of the anti-capitalist, leftist ideological terrorism of the 60s and 70s that was directed at wealthy industrialists, businesses and government.