When West Virginia Gov. Jim Justice announced that he was leaving the Democratic Party and returning to the Republican Party, the move highlighted once again the dominance of the GOP at the state level — and signaled to beleaguered Democrats the importance that the 2018 gubernatorial elections could play in starting a comeback.

With Justice’s switch, announced Thursday at a rally with President Trump, Republicans now hold 34 of the 50 governorships, tying the record for the most ever for the GOP. Democrats, who at the beginning of the Obama presidency held 28 governorships, have seen their ranks dwindle to just 15. At some point over the past decade, according to the Republican Governors Association, there has been a Republican governor in 46 of the 50 states.

Republican control of the states is even more lopsided when the partisan balance of state legislatures is included in the statistics. According to the National Conference of State Legislatures, Republicans now hold the governor’s office and control of the legislature in 25 states. Democrats enjoy total control in just six, with 18 states having split control. (Nebraska has a Republican governor and a unicameral, nonpartisan legislature.) Eight years ago, Democrats held the upper hand, controlling 17 states to nine for the Republicans.

For Democrats, the rapid loss of power in the states is both cause for alarm and some reason for hope. Republicans posted enormous gains in the states and in Congress in the midterm elections of 2010 and 2014. If it happened for the GOP, Democrats ask, why couldn’t it happen for them?

Midterm elections for a new president generally result in losses, sometimes substantial losses, and Trump currently suffers from the lowest approval ratings of any new president at this point in a first term. That’s compounded by the fact that the president and congressional Republicans have so far failed to enact a health-care bill, which could dampen enthusiasm among many GOP voters.

GOP strategists believe they must prepare for a political climate like that of 2006, when Republicans lost the House and surrendered their majority among governors.

A year from now, the atmosphere might look better, if the economy continues to expand and Congress enacts major legislation. If not, look for Republican gubernatorial candidates to distance themselves from Washington.

[Gov. Justice of West Virginia announces party change at Trump rally]

Democrats plan to make an issue of Trump in the state races. They also hope to see more intraparty turmoil over allegiance to the president in Republican gubernatorial primaries. That was a feature of the Virginia GOP primary earlier this year.

Even if there are favorable conditions for the Democrats, it is difficult to overstate the significance of these 2018 contests for their longer-term implications for the party. Winning more governorships offers at least two potential dividends. First, it could bring new faces to a party desperately in need of a reinvigoration through fresh, younger talent. Second, it could give Democrats more power in the redistricting battles that will take place after the 2020 Census and that will affect the shape of the House for a decade.

“The future of the Democratic Party really is at stake in these gubernatorial elections,” said Elisabeth Pearson, executive director of the Democratic Governors Association.

Over the next 15 months, there will be 38 gubernatorial races, starting this November with contests in Virginia and New Jersey. Democrats are heavily favored to pick up New Jersey, where current Gov. Chris Christie (R) has an approval rating in the teens. In Virginia, currently in Democratic hands under Gov. Terry McAuliffe, the race will be closer, but Democrats rate a narrow advantage.

The real test will come in November 2018, with the Republicans having to defend 26 states to just nine for the Democrats. Of those 26 Republican-held seats, about half will feature incumbents running (although several were appointed since 2014 and will be running on their own for the first time) while the remainder will be open seats and therefore potentially more attractive targets.

But here’s just one example of the challenge for Democrats. Republicans currently hold the governorships in Maryland, Massachusetts and Vermont, all deep-blue states presidentially. Yet the incumbents — Larry Hogan in Maryland, Charlie Baker in Massachusetts and Phil Scott in Vermont — are among the most popular governors in the nation. In a wave election, one or more could be vulnerable, but Democrats can’t count on easy pickups in states where their presidential candidates won by big margins last year.

[Republican lawmakers head home for recess with little to show]

Their best hopes in blue states will be in Maine, where outgoing Republican Gov. Paul LePage has been a source of constant controversy, and in Illinois, where Republican Gov. Bruce Rauner, a businessman who had never held office until he was elected four years ago, has been in a multiyear war with Democrats in the legislature. Meanwhile, Democrats could find themselves on the defensive in at least one other blue state, Connecticut.

Nor can Democrats look to many deep-red states for easy pickups. The nonpartisan Cook Political Report list of solid or likely Republican gubernatorial seats includes a dozen or so of these red states. Democratic strategists say they will not write off those states, arguing that they are determined to go after seats in all areas of the country.

As is so often the case in politics, the Midwest looms large in the gubernatorial elections. To mount a serious comeback, Democrats will need to show strength in the region that gave Trump the presidency over Hillary Clinton. In Wisconsin, Gov. Scott Walker (R) will be trying for a third term. Since winning the office in 2010, he has survived a recall election and a reelection campaign. Walker remains a polarizing figure, but the Democratic bench is not strong there.

Three Midwestern states will have open races: Michigan and Ohio, currently held by Republicans, and Minnesota, now in Democratic hands. Ohio went strongly for Trump, and Democrats have struggled in most statewide races in recent elections. Michigan narrowly backed Trump and probably will see a fierce battle for the governorship. Minnesota backed Clinton by a surprising small margin, and the gubernatorial race next year will be crowded and competitive. In Pennsylvania, incumbent Gov. Tom Wolf is seen by Republicans as vulnerable, and Democrats recognize he will have a serious challenge.

Other traditional presidential battlegrounds present opportunities for the Democrats, including Florida, New Mexico and Nevada, where Republican governors Rick Scott, Susana Martinez and Brian Sandoval are term-limited. Colorado Gov. John Hickenlooper (D) also is term-limited, giving Republicans an opportunity in a purple state.

The overlay of the coming redistricting battles adds an extra element of importance to 2017 and 2018 gubernatorial races. In 28 of the 38 states with elections this year or next, the governor has the power to veto a redistricting map produced by the state legislature. For Democrats, that provides the easiest route to check the power of Republican-held legislatures to draw maps favorable to their party — and vice versa.

Outside money will probably be pouring into many of these contests. Democrats have set up an operation aimed specifically at winning back House seats through more balanced congressional district lines, and that has heightened attention on the gubernatorial races. “Normally, our people are focused on federal races,” Pearson said. “This year, it feels like the difference between night and day.”

Next year’s congressional elections will draw outsized attention for the possibility of Democrats regaining control of the House and putting a huge roadblock in front of Trump and the GOP. But no one should lose sight of the longer-term importance of the gubernatorial races and what they will say about the rebuilding efforts of the Democratic Party.