The authors devote nearly 240 pages to the first sixty years of LDS history, 1830-1890, then only about 100 pages to the remaining hundred years (including the Epilogue, added for the second edition in 1992). But that's appropriate because in some sense the action in Mormon history ended in 1890. Before 1890 there was city building, migration, revelation, and conflict; after 1890, one has only bureaucratic retrenchment, doctrinal rationalization, and growth. The transition between the two periods is a pivotal moment in LDS history, termed "creative adjustment" by the authors, is covered in the twenty pages of Chapter 13, which I will comment on here.
In the first decade following 1890, the Church got its property back (or what was left of it) and Utah got statehood (in 1896). B. H. Roberts was elected to Congress in 1898, but the House (which decides its own membership disputes) refused to seat him because he was a known polygamist. Four years later, Reed Smoot, an Apostle but a monogamist, was elected to the Senate, which spurred another protracted political battle over whether he could assume his seat (showing, I think, that the conflict was ultimately about the Church, not polygamy). He did, but not until after the Senate held hearings for a couple of years, including hauling President Joseph F. Smith off to Washington as the star witness before the Committee on Privileges and Elections.
Those events underline the extent to which politics assumed an important role in "the new Utah." Party organization, affiliation, and influence played as large a role in changing the shape of Utah as the presence of legitimately elected Mormon officials in the national government. In turn, the national parties schemed to secure support from Utah politicians and voters (and thus garner the votes of the elected representatives in Congress). I get the sense that energetic politics kind of filled the void left by the end of direct conflict with the US government. Investment in Utah's fledgling economy by economic interests from the East followed as well, augmenting or displacing the initial enterprises set up during the pioneer years. Here's the paragraph that sums up the whole experience of "creative adjustment":
The survival of the Church of Jesus Christ of Latter-day Saints had thus required certain anguishing accomodations to American culture: Plural marriage was abandoned; the People's party was replaced by mainstream partisan politics; and group economics, no longer feasible with the separation of church and state, disappeared as competitive individualism was embraced. . . . The church was, in effect, reoriented to incorporate the standards of social, political, and economic behavior imposed by American society, while at the same time it attempted to retain as much of the "Kingdom" outlook as possible.