Last night was a banner night for conservatives, who defeated a number of measures in liberal strongholds, including a transgender bathroom ordinance in Houston, a $15 minimum wage ordinance in Portland, Maine, and a proposed law restricting AirBnB rentals in San Francisco. But the most consequential GOP victory came in Kentucky—a deep red state in presidential elections that has nonetheless had Democratic governors for 40 out of the last 44 years—where the conservative-populist insurgent Matt Bevin won the statehouse for Republicans by an almost nine point margin.The Republican victory in Kentucky underscores the extent to which the ranks of elected Democrats outside of 1600 Pennsylvania Avenue have been thinned since 2010. It’s important not to overstate President Obama’s responsibility for these losses—the party that holds the White House has historically suffered setbacks in off-year elections. Yet, there are reasons for Democrats to be worried, over the long term, about the extent of the clobbering in state and local elections they have endured over the past six years.The Democrats have constructed a political coalition heavily reliant on young people, minorities, and urbanites. As Democrats are fond of repeating, these voters have helped deliver the popular vote in presidential elections to the Democrats in five out of the last six cycles. But this coalition is not nearly as well suited to elections for Congress and state legislatures, because these voters are “inefficiently distributed” (that is, packed around urban areas) or to off-year elections in general, because they are less likely to show up when a presidential candidate isn’t on the ballot.This creates an interesting dynamic. Because the Democrats’ ranks have been eviscerated at lower levels of office, the stakes for winning the White House couldn’t be higher. As we we wrote last month, “if the party loses the White House 2016, it will have almost nothing left.” The prospect of losing everything creates an incentive for Democrats to double down even further on their presidential coalition (see, for example, Hillary Clinton’s full-throated endorsement of the Houston transgender ordinance). But this strategy—of appealing more and more strongly to the national base rather than reaching out to new segments voters—makes them even less competitive in off-year and state-level elections.So long as the Democrats can continue to hold the presidency, and so long as the powers of the presidency continues to grow, this may be a solid electoral strategy. But it’s a risky bet. If a Republican is elected president, the vulnerabilities of the current Democratic coalition will be exposed. A strong national coalition is useless if it doesn’t give you the tools to wield actual power.