Was Otto von Bismarck a sly opportunist or a powerful statesman?
Bismarck was a key player in the unification of Germany, as he successfully subdued the Austrian threat and solidified Prussian control over Germany, after Prussian victory in the Austro-Prussian War (1866). In 1871 after the Prussian victory in the Franco-Prussian War, Germany was unified under Prussian King Wilhem I. Bismarck was a Prussian patriot, not a German nationalist. As German Chancellor he exercised realpolitik which was aimed at strengthening Prussian hegemony through a strong continental European Germany. He used war and diplomacy as tools to achieve this aim. Bismarck wanted Germany to be powerful thus initially he was solely interested in continental Europe. However Bismarck was compelled to colonise the world, as a colonial school of thought developed in Germany. Although Bismarck personally opposed this as he believed German imperial expansion would require a strong navy and to construct one would lead to a dangerous rivalry with the British Empire. This would be later vindicated in the Dreadnought race. Bismarck was a great balancer of political affairs. He successfully isolated France through the Dreikaiserbund which was a political alliance between Germany, Austro-Hungary and Russia. He also acquired Tanganyika (Kenya), other parts of Africa and German New Guinea (whom Bismarck Sea is eponymous to). This appeased German colonialists. Bismarck was able to secure Pax Germania. However the outspoken, vacillatory and bombastic Wilhem II who had agressive designs on Europe sacked Bismarck in 1890 as both of there foreign policies were incongruent. From 1890 to 1914 Germany headed on a disasterous path to world war. Bismarck rightly predicited that if a major war conflagrated it would originate from the Balkans:
"One day the great European War will come out of some damned foolish thing in the Balkans."
– Reported by Winston Churchill, The World Crisis, C. Scribner's Sons (1923) p. 195, attributed to Bismarck by Albert Ballin

I would conclude that Bismarck was a powerful statesman who adeptly exploited a situation through dexteriously isolating France, appeasing the colonial school and strengthening Germany under Pax Germania.

