Editing Bosporus (section)

=== Turkish republican era (1923–present) ===
Following the [[First World War]], the 1920 [[Treaty of Sèvres]] demilitarised the strait and made it an international territory under the control of the [[League of Nations]]. This was amended by the [[Treaty of Lausanne (1923)]], which restored the straits to Turkey but allowed all foreign warships and commercial shipping to traverse the straits freely. Turkey eventually rejected the terms of that treaty, and remilitarised the straits area. The reversion was formalised under the [[Montreux Convention Regarding the Regime of the Turkish Straits]] of 20 July 1936. That convention - which is still in force - treats the straits as an international shipping lane except that Turkey retains the right to restrict the naval traffic of non–Black Sea states.

[[File:Istanbul panorama and skyline.jpg|thumb|upright=2|Modern (2012) view of the European side of Istanbul from the southern entrance to the Bosporus]]

Turkey was neutral in the [[Second World War]] until February 1945, and the straits were closed to the warships of belligerent nations during this time, although some German [[auxiliaries|auxiliary vessels]] were permitted to transit. In diplomatic conferences, [[Soviet Union|Soviet]] representatives had expressed an [[Turkish Straits crisis|interest]] in obtaining naval bases on the straits. This, together with Stalin's demands for the restitution of the Turkish provinces of [[Kars Province|Kars]], [[Artvin]] and [[Ardahan]] to the [[Soviet Union]] (which were lost by Turkey in the Russo-Turkish War of 1877–1878, but were regained with the [[Treaty of Kars]] in 1921), was a consideration in Turkey's decision to abandon [[country neutrality (international relations)|neutrality in foreign affairs]]. Turkey declared war against Germany in February 1945, but did not engage in offensive actions.<ref>{{cite web|url=http://www.fpri.org/enotes/20030110.balkansturkey.torbakov.turkeypostsovietspace.html |title=The Turkish Factor in the Geopolitics of the Post-Soviet Space |first=Igor |last=Torbakov |work=E-Notes |publisher=Foreign Policy Research Institute |date=2003-01-10 |access-date=2010-06-08 |url-status=dead |archive-url=https://web.archive.org/web/20100731000411/http://www.fpri.org/enotes/20030110.balkansturkey.torbakov.turkeypostsovietspace.html |archive-date=2010-07-31 }}</ref><ref>{{cite web |url=http://www.robertcutler.org/ch91dc.htm |title=[Russian and] Soviet Relations with Greece and Turkey: A Systems Perspective |first=Robert M. |last=Cutler |date=1999-03-28 |access-date=2010-06-08}}</ref><ref>{{cite news|url=http://www.todayszaman.com/tz-web/yazarDetay.do;jsessionid=DC0C8B5C41104733FE75243EF5E99B20.node1?haberno=36433 |title=Against who and where are we going to stand? |first=Ali |last=Bulaç |date=2009-05-04 |work=[[Today's Zaman]] |access-date=2010-06-08 |url-status=dead |archive-url=https://web.archive.org/web/20090504145149/http://www.todayszaman.com/tz-web/yazarDetay.do%3Bjsessionid%3DDC0C8B5C41104733FE75243EF5E99B20.node1?haberno=36433 |archive-date=2009-05-04 }}</ref>

Turkey joined [[NATO]] in 1952, thus affording the straits even more strategic importance as a commercial and military waterway.

During the early 21st century, the [[Turkish Straits]] have become particularly important for the oil industry. Russian oil, from ports such as [[Novorossiysk]], was exported by tankers primarily to the U.S. via the Bosporus and the Dardanelles straits.