BALTIMORE -- A tuba and banjo duo dressed in saddle shoes, khakis and button-down shirts plays polkas and foxtrots by a set of escalators at the Baltimore-Washington International Airport on Friday morning. A nearby shoeshine man takes a break from his work to watch them and smile. It's a lighthearted moment that contrasts strongly with the scene a few feet away.
There, in security lines for Terminal C, passengers intentionally avoid making eye contact as they shuffle toward whirring machines, removing their shoes and preparing for the possibility of delay, interrogation or arrest. Videos on wall monitors broadcast exhortations from government officials to be cautious and watchful. At transit stops around the airport, which serves the US Capitol and other national tourist attractions, signs tell people to watch for suspicious activity.
The government posters have been present for a long while -- parodies are common on the Internet by now -- but in the days since two bombs killed and maimed fans at the Boston Marathon, their ability to project a genuine aura of foreboding has ever-so-slightly
expanded its reach.
In few places is that security dichotomy -- how to balance paranoia against sanity, safety against liberty -- tilted more toward a total surveillance state than in London, which hosts its own marathon Sunday.
Londoners have a long history of being snooped on, but in recent years the pace has accelerated with signs openly blaring Orwellian slogans such as "Secure beneath the watchful eyes" while police drones occasionally zip overhead during big events. According to the book 'Big Data,' a 2007 audit of George Orwell's old neighborhood in London found 30 surveillance cameras within 200 yards of his former apartment.
That surveillance mindset has been amped up this week in Britain's largest city, first for the funeral of former prime minister Margaret Thatcher, and continuing for the marathon, with police authorities posting warnings of extraordinary stop-and-frisk measures in the name of security.
Those measures do not come in a historical vacuum, of course. Much of the worry can be blamed on bomb attacks by a radical Islamist group in summer 2005, along with bombings by the Provisional IRA and related groups over recent decades.
The last major Provisional IRA violence in London was in 1996, when bombs in Manchester and London's Canary Wharf caused more than £500m in damage, and only minority branchoff groups have been active since then, according to Andrew Sanders, the author of "Inside the IRA."
"[Sinn Fein's political success in the 1980s] drove the message home to Irish republicans that politics could bring their struggle for Irish unification into the political arena," Sanders wrote in a Friday email. "Support for armed struggle only ever existed among the minority of Irish citizens but political struggle was far more legitimate."
That doesn't mean that some groups don't still have the ability to wreak havoc -- Sanders
cites Irish splinter groups' access to explosive Libyan semtex, used in the recent murder of PC Ronan Kerr in Omagh -- but it takes significant power away from efforts to raise funds and support for such violent activity: A poll Sanders cited in a 2012 article put even support for unification itself at a historic low of seven percent. Support for violence is nearly certain to be significantly lower.
With American media now jumping on the possibility of a Chechen connection to the Boston bombings -- two Boston suspects have been identified as being from a region near Chechnya, a Russian region with a strong separatist streak -- Sanders is asked about whether he has any personal experiences that might give him insight onto possible ethnic profiling in London. He replies that while he is from Scotland and didn't face profiling himself, his wife is Northern Irish.
"They had to plan their holidays around at least an hour delay on their way to the airport because of the necessary security checks which were carried out by armed soldiers," Sanders states.
"Indeed, it's only in recent years that the search post on the way to Belfast International Airport has been removed. I think the major issue for them was that despite the conflict, people often just assumed them to be Irish."
As a worst-case type of scenario, Sanders cites the Guildford Four incident, in which multiple people "were arrested and jailed for nothing more than being Irish in London during the 1970s."
The marathon itself will move ahead as planned on Sunday, with Geoffrey Mutai, Stephen Kiprotich, Tsegaye Kebede and other international running stars lining up for an early Sunday start. (Three-time London champion Martin Lel and two-time world champion Abel Kirui pulled out at the last minute with a hamstring injury and a stress fracture, respectively.)
Also in the running for the men's race will be defending champion Wilson Kipsang, world record holder Patrick Makau and what has generally been deemed by many in the media to be the most potent men's field ever assembled for a marathon, the largest contingent of which is made up of Kenyans, who often work as a team to push each other.
"I think we want to run as a team and try to run a faster time to maybe break the course record and see how far we can go faster," Kenyan Kipsang told Reuters on Wednesday.