Here is an observer's guide to some races of national importance:
-- Arizona governor. The last three governors of the state were women, one Democratic and two Republican. Of the 14 governors since mid-century, seven were Republicans and seven were Democrats. Three Arizonans -- one Democrat who was not nominated, two Republicans who were -- have run for president in the past half-century.
All that suggests the state is a model of political balance. It is not. Since the middle of the 20th century, the state has voted Republican in every presidential election but one (1996, when Bill Clinton defeated Robert J. Dole).
This gubernatorial race may signal how Arizona, and perhaps America, will lean in the future.
-- Iowa Senate. Tom Harkin has been an unbending oak in Iowa politics for a generation, first as a crusading House member, later as a liberal stalwart in the Senate. He's retiring. The race to fill his spot is important, and not only because the destiny of every Democratic-held Senate seat is important.
The issue here is the political profile of Iowa, the site of the first presidential caucus in 2016. The state's gubernatorial race won't tell us much significant. The incumbent, Republican Gov. Terry Branstad, is running for his sixth term -- if he wins, he'd be positioned to be the longest-serving governor in American history -- and so the gubernatorial race is less about issues than it is about Branstad.
The focus instead is on the GOP Senate primary, with special attention on whether the nominee is identified with what are known in Iowa as "Liberty Republicans," who are basically members of the Tea Party, or with party regulars.
-- Illinois governor. A Bruce Rauner victory in the gubernatorial race in Illinois this fall would send an especially powerful message.
Rauner, who owns a share of the Pittsburgh Steelers, is the former chairman of a private equity firm in Chicago. He is a novice to elective politics and his is a traditional Republican profile, emphasizing business values, government efficiency, reduced spending and lower taxes. To that he has added a vow to cut the state's minimum wage.
His opponent is Gov. Pat Quinn, a traditional Illinois Democrat with traditional experience (six years as lieutenant governor, four as treasurer) but an untraditional Democratic problem -- opposition from unions, in large measure because of his support for a state pension plan that undermines public employees' retirement plans.
This race will indicate whether the Democrats' populist themes (increase millionaires' taxes and keep the minimum wage above the federal level) or the Republicans' populist themes (cut taxes, improve the commercial climate) prevail among alienated voters in a big state, providing a hint of which campaign strategies might be effective in the 2016 presidential race.
David M. Shribman is executive editor of the Post-Gazette (email@example.com).