Both manuscripts as well as the early editions and the RLDS textual tradition have the plural governments, which is unexpected in current English. The 1841 British edition replaced the plural with the expected singular, and the LDS text continues to have the singular government. One could argue that here Oliver Cowdery accidentally added a plural s in 𝓞, just as he apparently did nearby for the word compound (see under Alma 43:13).
On the other hand, the plural governments is found in one other place in the text:
𝓞 is not extant for this second occurrence, but it probably read in the plural (as it does here in Alma 43:17). When Oliver Cowdery copied the text from 𝓞 into 𝓟 in the Helaman passage, he initially wrote the expected singular, government (spelled as goverment, according to normal pronunciation). Virtually immediately Oliver corrected the number by inserting inline the plural s (there is no difference in the level of ink flow for the s ). Since the plural is the difficult reading, 𝓞 probably read in the plural in Helaman 5:2. And there the plural has been maintained in the text, perhaps because it is conjoined with the plural laws (“their laws and their governments”). Here in Alma 43:17, governments is conjoined with the singular noun command, which may help explain the replacement of governments with government. But the plural definitely appears to be intended in both Alma 43:17 and Helaman 5:2 and will be followed in the critical text.
The Oxford English Dictionary lists the following relevant definition (3a) under government: ‘the office or function of governing or ruling; authority to govern’. This definition clearly applies to Helaman 5:2 (“their laws and their governments”). Then the OED adds a more specific definition, one marked as obsolete: “the command of an army or fortress” (with at least one citation, from James Tyrrell in 1700: “he was persuaded to accept the government of Dover castle”). It is this restricted sense of government under definition 3a which is apparently being used in Alma 43:17: there were multiple armies and fortresses as well as multiple wars that Moroni had the government of, so the plural phraseology “the governments of their wars” can apply to Moroni.
Summary: Restore in Alma 43:17 the plural governments, the reading of all the earliest sources (including 𝓞); Helaman 5:2 provides additional support for the use of the plural governments in the Book of Mormon text.