Most of the Democratic presidential hopefuls agree that the United States is in dire need of big systemic changes.

From calls to abolish the Electoral College or the Senate filibuster to advocating packing the Supreme Court, different candidates support different reforms. But almost all of these proposals have a common and surprising admission underpinning them: that Democrats can't enact their agenda without changing the rules of the game because they face an intractable structural disadvantage, especially evident in the Senate.

To put it bluntly, this undersells the Democrats' capacity to win. The state of play in American politics can quickly and drastically change, and demographics indicate that another wave of change might be in the offing.

Driving the push for big structural change is the perception that Republicans have a built-in and durable advantage in both the Senate and the Electoral College, thanks to each state having two senators and at least three electors in presidential contests. This leads to the overrepresentation of rural whites who vote strongly Republican.

But such an understanding presupposes a static playing field when American politics is actually quite fluid.

West Virginia was one of only six states (plus the District of Columbia) to vote for Jimmy Carter's reelection in 1980, and one of only nine states plus D.C. to favor Democrat Michael Dukakis over George H.W. Bush in 1988. But in 2000, George W. Bush captured the state, and no Democrat has come close since. West Virginia's politics shifted down ballot as well: Heading into the 2000 election, Democrats controlled all five of the state's congressional seats. Today, they are down to one seat and even popular Sen. Joe Manchin saw his margin shrink from roughly 24 points in 2012 to 3.5 points in 2018.

And West Virginia is not an anomaly: On Election Day 2004, Democrats controlled all six of the House and Senate seats in North and South Dakota. Today, they control zero.

The rapid transformations over the past 15 years haven't just moved states towards Republicans either. On Election Day 2006, Republicans controlled both Virginia Senate seats and eight of 11 House seats; Democrats hadn't won the presidential vote in the state since 1964. Today, by contrast, they control both Senate seats and seven of 11 House seats, and have won the state's presidential electors in three consecutive elections.This fluidity explains why Democrats are not doomed to permanent minority status.

Today, Democrats and allied independents hold 47 Senate seats. Additionally, there are two Republican senators in states won by Hillary Clinton in 2016, and two more in Pennsylvania and Wisconsin, states the Democratic presidential nominee won in six and seven consecutive elections respectively before 2016 and in which the party won gubernatorial campaigns in 2018.

More importantly, there is a group of Sun Belt states (Arizona, North Carolina, Georgia, and Texas) that collectively have seven Republican senators but are showing real signs of a Democratic resurgence. In Arizona, Democrats won a Senate race in 2018 for the first time since 1988, and while Mitt Romney won the state's presidential vote in 2012 by roughly 9 percentage points, Trump only captured it by 3.5 points. Similarly, in Texas and Georgia, Trump's margins of victory were 7 points and 3 points smaller than Romney's. Additionally, in 2018, Democrats Beto O'Rourke and Stacey Abrams came closer to winning a Senate election in Texas and gubernatorial election in Georgia than any Democrats this century.

Demographics indicate these narrowing margins aren't a fluke: The Cook Political Report's David Wasserman noted that white college degree holders are the demographic trending most towards Democrats, and of the 15 states where college degree holders make up the largest percentage share of white voters, 14 routinely vote for Democrats statewide. The 15th? Texas, which ranks 12.

Wasserman offered another data point that shows why Democrats are becoming more competitive in these places: In only 11 states and the District of Columbia do large metropolitan areas cast more than two-thirds of the statewide vote. Of the 12, nine are reliably blue states, one (Nevada) has swung towards the Democrats in the last decade, and the other two are Arizona and Texas. Other research indicates that younger, left-leaning voters are flocking to Sunbelt suburbs in places like Atlanta and Charlotte, further bolstering Democrats' hopes.

Toss in Florida, which has two Republican senators and leans right only by a razor thin margin, and Democrats have a pathway to 61 Senate seats without capturing any seats in more hostile territory. That's enough to overcome a filibuster.

Given this achievable pathway to both an Electoral College majority and a Senate majority or supermajority, undertaking drastic remedies doesn't make sense, because they'd come at a high cost: undermining the legitimacy of the policies that Democrats enact subsequently. Americans who disagree with these policies would see them as a byproduct of a ruthless willingness to do anything to force them into law. This lack of legitimacy would leave initiatives far more vulnerable to repeal and make improving or tweaking them — necessary with most major reforms — impossible unless Democrats maintained unified control of government.

None of this is to say that reforms may never be necessary to update the structures of our government to reflect modern realities. Nor is it to say that some reforms aren't already good ideas (like giving American citizens in places like Washington, D.C., and Puerto Rico statehood and full congressional representation) But before taking drastic steps that further poison our politics, Democrats would be wise to craft an appealing agenda that can achieve their preferred policies the old fashioned way. It's entirely doable and would better position them to enact durable change.

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