The Scramble for Africa saw Ethiopia not only remaining uncolonized but also an expansion of territory. How did Ethiopian imperial policy compare to those of European colonizers?

This is, in large part, the story of Negus Menelik of Shewa (Shoa), prior to and shortly after his ascent to the throne as Negusa nagast (Emperor) in 1889. His policy had several pieces that were defensive, but not necessarily reactive; one of them was empire-building. While his predecessor Yohannes IV fought against the Mahdi in neighboring Sudan (which eventually cost him his life), this wasn't really done with an aim to expanding the empire. Menelik expanded Shewa at the same time in order to shore up his position relative to Yohannes, who had beaten him out in the struggle for succession between 1868 and 1872. It also positioned him to pull other nobles and leaders into his orbit at that time, because he maintained an active foreign policy and, through his trusted minister Ras (prince) Makonnen, was aware of how Europeans insinuated themselves and took over territories. To a significant degree, then, Ethiopian empire-building was defensive but not entirely reactionary. This distinction is of course lost upon the non-Christian people in former Adal and areas farther to the south that Menelik took over, but the key point is that he built a significant power base that way.

Explosive expansion, or oceanic activity, was not part of this because it could only cost him in money and people. Tewodoros II (whom the British destroyed at Magdala in 1868) and Yohannes IV had grander titles and ambitions within Christendom, but Menelik sought to be more consultative and deliberative in making his moves. Menelik wasn't going to butt heads with the kingdoms of the interlacustrine region [edit: e.g., Buganda, Bunyoro, Rwanda] because they were too powerful to be worthwhile, for example, and besides Europeans were busy insinuating themselves in the late 1880s and early 1890s culminating in the victory of the Protestant Bugandan nobility. In this way, Menelik's acquisitions were denials of areas to foreign powers; he moved into areas with weak or absent claims, following the dictum of Berlin even if not knowingly.

Sometimes this came before Berlin in 1884/5, as the European acceleration in Africa was well known in Ethiopian circles by that time. Menelik signed a boundary convention between Shewa and Italy on 21 May 1883. A tripartite peace treaty came into effect between Egypt (under Tawfiq), the British, and Yohannes IV to end conflict between Egypt and Ethiopia (and thus Britain) in June 1884. Although southern boundaries around Ethiopia's expansion were only settled in general terms after Adwa, and in specific terms around 1907, the fact that the Ethiopian court undertook binding agreements over territory and sovereignty in terms and legal forms that Europeans recognized served as a bit of a brake. Compared to treaties of the 1840s that were about friendship and consultation, these represented a much tougher legal hurdle. So in that sense, Ethiopian imperial policy regarding self-definition shared a great deal with European counterparts. The power differential, and the tendency of the Europeans to behave as a bloc, of course made the actual process different. Menelik, for example, could not refuse to sign Wuchale (Wichale) in 1889 despite its offensive sovereignty-infringing Article 17 (lest Italy back some enemy of his), and once he activated his power base, moved the capital to Addis, and consolidated his court, he repudiated it, which precipitated the Italian campaign.

In terms of other policies, that's harder. Menelik ruled indirectly in areas that were seen as reasonably secure or dangerous to push (like Gojjam, to the west). But the explosive growth of the kingdom (and thus empire) to the south and southeast, mainly in the 1880s and spurred in part by the famines of the first rinderpest era, was often quite bloody and resulted in direct appointment of leadership but the conciliation of local rulers wherever possible, in a partial analogue to a mode of indirect rule. In the southwest, in the 1890s, it was often much less so, and Menelik could step into the role of patron in the place of the collapsing Mahdist state in the Sudan. During the 1890s there was some effort to distribute food aid and reward loyal subject rulers, as surely as Menelik used his military--with foreign arms, increasingly--to punish the recalcitrant. In terms of cultural and social policy, I've seen less information; Menelik does not seem to have demanded much change, aside from his solemn assurance to the British that his kingdom--like Ethiopia itself--would not trade in slaves. Such a policy was helpful for reconciling people to the more temporal demands of the state for fiscal, logistical, and personnel support; trying to extirpate Islam, for example, in areas ruled by compliant Muslim rulers would be courting internal disaster and external opportunism.

The overriding policy goals were ones of security and centralization of the state, because Ethiopia (and Shewa) understood the threat under which it existed. It's harder to posit what policy would have been like had European empire not been so strident at the time; Aksum held tributary power over large parts of the Hejaz (in Arabia) many centuries before, but Ethiopia was an agrarian and territorial power, which meant that although some forms of its imperial rule were similar, and some of the expansion produced structures we might recognize as being part of the economics of empire, the motivations were not exactly the same. That the people and lands were contiguous, and shared a long history of interaction (and enmity, in the Awash valley for example), also certainly played a role in the way the political and social orders shook out.

The details of this expansion come from the second edition of Bahru Zewde's A History of Modern Ethiopia 1855-1991 (London: James Currey, 2001), but some of the foreign and strategic considerations come through in Ray Jonas's The Battle of Adwa (Cambridge: Harvard, 2011). The treaty details are in the 1908 third edition of Edward Hertslett's The Map of Africa by Treaty 3 vols. (London: Frank Cass, 1908), 419-463 passim.