JUST LONG ENOUGH TO PASS AMNESTY AND SOME OBAMACARE TWEAKS:

[I]magine that Clinton prevails in November. If so, the most likely outcome is a continuation of the recent pattern of resounding GOP victories in midterm years. In 2018, Democrats will defend Senate seats they won in 2012 in several red states, including Indiana, Missouri, Montana, North Dakota and West Virginia. West Virginia's Joe Manchin famously shot a copy of the cap and trade bill in a 2010 campaign advertisement -- but even excellent marksmanship might not be enough in a third consecutive midterm wave for the GOP.

In addition, some of the most important aftershocks of the 2016 election are likely to be felt not in Washington but in state capitals across the country. In 2018, 36 states will choose governors. As I've pointed out before, our elections for governor increasingly track national trends. Governors are typically powerful officials in their own right, with substantial control over state budgets and policy. But even for those who care about power only at the federal level, there is good reason to care about the 2018 governors' races: In many states with multiple House districts, those governors will have veto power over their states' redistricting processes after the 2020 census. Over the course of the Obama presidency, anti-Obama voting in non-presidential years is a major reason why the Democrats have lost a net of 11 governors' seats.

Likewise, 2016 has critical implications for state legislative elections. Political scientist Steven Rogers has shown that presidential approval is a powerful predictor of voting in state legislative races. Since Obama became president, the same dynamics have cost the Democrats approximately 818 seats in state legislatures, and they have lost control of 29 net chambers in state legislatures. Sure, holding the presidency allows a party to pursue its agenda at the federal level. But in recent decades, that pursuit has come at a remarkable down-ballot cost for Democrats and Republicans alike.

To explain why the electorate has alternated between leaning Democratic in recent presidential years and Republican during midterms, Obama argued that Democratic-leaning constituents are less likely to vote in midterm years. There's some truth to that. But it's not the main force behind the recent swings, as FiveThirtyEight's Harry Enten has shown. Think about the math: Each voter who sits out a midterm costs his party one vote, while each voter who switches parties adds a vote to the new party while taking one away from the old party. The more powerful engine for change is that voters are changing their minds -- and for decades, they've leaned against the party holding the White House.

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