How and why can Turkey become involved in the current crisis on Crimea?
Undoubtedly, Turkey must be involved to some degree. The peninsula, contested by Russia and Ukraine, is separated from the Turkish coast by less than 300 kilometers. In addition, Turkey is a member of NATO and a a close ally of the USA, which is increasingly confronting Russia over the crisis. And Turks feel a close ethnic and religious kinship with the Crimean Tatars, the oft forgotten third party in the Crimean conflict.
The geographical proximity of Turkey to Crimea is straightforward to understand. Recent reports from Ukraine suggest that as many as 30,000 Russian soldiers are now present in Crimea, while more could arrive to the peninsula from Russia quickly across the narrow Kerch Strait. At the same time, while the Russian Black Sea Fleet may not be in an impressive state it still retains a few vessels capable of engaging in combat operations, as demonstrated during the Russo-Georgian war in 2008. And as a reminder that a Russian military threat cannot be ignored right now, recently and repeatedly Turkish military jets have had to scramble in order to deter Russian jets from flying along the Turkish coastline. (http://uk.reuters.com/article/2014/03/07/uk-turkey-russia-idUKBREA2612720140307)
The Turkish forces are not pushovers. The Turkish military is twice the size of that of Ukraine (www.cia.gov) and has retained its combat readiness over many years in an oft unstable region. While most of the Turkish fleet is normally located in waters west and south of the country, the fact that Turkey controls the Bosphorus Strait, providing access to the Black Sea, would make it easy for Ankara to quickly project considerable power against the Ukrainian coastline.
Turkey, though, has several reasons for not doing so. First, any genuine military move to help Ukraine retake Crimea would provoke significant opposition from Russia and would almost certainly end in major bloodshed, a massive and highly unpredictable escalation of the current crisis. Also, Turkey has a number of trade and energy agreements with Russia. 58% of Turkish gas supply comes from Russia (http://www.al-monitor.com/pulse/originals/2014/03/turkey-still-needs-russian-gas-via-ukraine.html). Similarly, Russian-Turkish trade allegedly stood at $34bn last year and leaders of the two states happily declared their intent to increase trade volume in future. (http://en.ria.ru/world/20131123/184874427/Russia-Turkey-Vow-to-Boost-Bilateral-Trade-Tourism.html).
Turkey cannot ignore events in Crimea, though. Having acceeded to NATO in 1952 during the first enlargement of this organisation, Turkey had almost 40 years of experience being on the front line of the Western struggle against the Soviet Union. This, of course, does not mean that the Turkish leadership today views Russia as a continuation of that enemy, but it does mean that Turkey had the chance to build up an institutional culture around cooperation with the USA, in particular. And, as was also seen during the Russo-Georgian war in 2008, the USA is using such affiliation to send military vessels through the Bosporus Strait and thus closer to the Russian and Ukrainian coastlines. ( http://uk.reuters.com/article/2014/03/07/uk-ukraine-crisis-usa-warship-idUKBREA260ZB20140307) The American destroyer, which now entered the Black Sea, may officially prepare to conduct exercises with the Bulgarian and Romanian navies, but it also serves as a reminder to Russia that the USA is watching.
Now, Turkey cannot just let the entire US navy through Bosporus. Ankara is governed here by the 1936 Montreux Convetion, signed by a group of states including Turkey, the Soviet Union, France, and Britain, and governing the size and number of military vessels permitted access from the outside to the Black Sea at any one time. (http://sam.baskent.edu.tr/belge/Montreux_ENG.pdf) As Moscow showed in 2008, when the arrival of American military vessels quickly brought threats of trade sanctions against Turkey, Russia is a stickler for international law here. Consequently, the Turkish fleet is currently preparing to depart not for the Black Sea but for Africa (http://www.todayszaman.com/columnist/lale-kemal_341371_turkish-navys-long-african-tour-at-a-time-of-crisis-in-black-sea.html) while it is unlikely that the USA will send to the Black Sea forces anywhere near the size required to worry Russia.
Indeed, right now Turkey does not need a clash with Russia. In domestic politics, the Turkish President and Prime Minister, once again, disagree - now on the limits of freedom on the internet (http://uk.reuters.com/article/2014/03/07/uk-turkey-erdogan-idUKBREA2609E20140307). Of possibly greater worry to the Turkish regime, its former army chief has been released from prison after two years, as the life sentence he received for plotting a coup against the state was deemed unconstitutional by the Turkish constitutional court. (http://uk.reuters.com/article/2014/03/07/uk-turkey-general-idUKBREA2612Y20140307). So Ankara really does not need to get involved in a Crimean imbroglio right now.
Nevertheless, Turkey has unequivocally stated that Ukrainian territorial integrity is of central importance for Ankara. (http://en.trend.az/news/politics/2250492.html) Partly, this is due to Turkish discomfort with separatist movements and secession, in general, pace the Kurds. Yet it is also due to the 13% of Crimeans who are Tatars and whom Turkey has long declared kinship. In the current situation, again the Turkish Foreign Minister has made clear that his country will do everything necessary to ensure the "peacefulness and composure" of this Crimean minority (http://en.cihan.com.tr/news/Turkey-will-continue-to-protect-Crimean-Tatars-rights-says-Davutoglu_5273-CHMTM3NTI3My8xMDA1). Now, the Tatars have not exactly benefitted from Ukrainian rule in the last twenty years, yet they have consistently taken the side of Ukrainians against the Russian majority on Crimea. For this reason, and because Turkish Prime Minister Recep Erdogan has a history of bullish support for perceived kin abroad, it is certain that Turkey will continue to follow developments in Crimea closely, and possibly become more involved in the near future.