What’s unusual about these protests, however small, is that they have happened at all. Ruled until the mid-’80s by a hard-line military regime, Turkey has never been particularly tolerant of civil disobedience. Yet the earnest ecowarriors on the Bosporus are not only tolerated but positively encouraged by the authorities. The reason? They are at the front line of a new geopolitical conflict pitting Turkey and Western interests against an age-old rival, Russia.

For once, the ecologists and the state have found themselves on the same side. At stake is the export route for the biggest oil deposits discovered in three decades–the huge Kashagan and Tengiz oilfields in Kazakhstan. The only existing pipelines to the north Caspian, including the largely U.S.-funded Caspian Pipeline Consortium’s newly built line, all run to the Russian Black Sea port of Novorossiysk. From there the oil is put into tankers and shipped to the rest of the world. That’s where the Bosporus comes in. The 19-mile waterway is a mere 700 meters wide at its narrowest point. Navigating its nine sharp bends is a tanker captain’s nightmare. Twelve million people live along the strait, and a major accident would be an ecological disaster of epic proportions. But when all the pipe-lines into Novorossiysk start pumping at full capacity, as Kazakh fields are opened up over the next four years, the number of supertankers going through the strait could easily quintuple.

That has the environmentalists up in arms. But what worries Western and Turkish politicians more are the strategic implications. If all of Kazakhstan’s oil were exported via Novorossiysk, Russia would have a total monopoly over Kazakhstan’s export routes–bringing Kazakhstan irrevocably back into the Russian sphere of influence. Turkey–and the White House–have therefore long favored sending at least a chunk of Kazakhstan’s oil via an alternative pipeline bypassing Russia, stretching instead from Azerbaijan’s capital, Baku, to the Turkish Mediterranean port of Ceyhan.

Last week those hopes took a giant step forward. After three years of hesitation, British Petroleum formally committed itself to the $2.8 billion project. The new pipeline will transport the bulk of Azerbaijan’s oil and could easily carry Kazakhstan’s, as well, if the necessary connections were built. But will they be, and if so, what portion of Kazakhstan’s crude would flow to Ceyhan versus Novorossiysk? That’s quite literally the trillion-dollar question. “Diplomatically, Kazakhstan is in play,” says a U.S. diplomat in the region.

Which brings us back to the Bosporus. How much oil can go though the strait? The answer to that will be the upper limit of the Caspian oil Russia can export–and by extension, the upper limit of Russia’s power over Kazakhstan. Not surprisingly, there’s little agreement on the issue. Turkey has been pressing to redefine the 1936 treaty declaring the strait to be international waters, though giving Turkey some authority to regulate traffic. Russia, predictably, adamantly opposes any such changes, arguing that no nation can restrict the volume of tanker traffic through the strait.

That’s where the ecowarriors come in. The more public protest, the more ammunition the Turkish government has for more strictly regulating–and limiting–traffic in the strait. The Turkish government is reluctant to risk a direct confrontation with Russia. But Ankara can plead voter outrage and ecological concerns as compelling reasons for intervening. Such geopolitical considerations do not worry One Earth activists like Orhan Kirdar. “What we are showing here is that ordinary people can change politics,” says the balding English teacher. With a little encouragement from Ankara and the White House, that is.