Like my colleague George Packer and many others, I feel some trepidation about the upcoming 2016 Presidential election. What with the sheer length of the process, the obscene amounts of money involved, and the prospect of another Bush vs. Clinton contest following the primaries, it’s not surprising that a lot of Americans, and particularly progressives, aren’t exactly enthused.

But before you think of moving to Canada for a year and a half, or tuning out and reading Tolstoy and Dickens, take a peek at a new analysis of the American political firmament by Sean Trende and David Byler, of the Web site Real Clear Politics. It’s a data-driven article that examines what’s happening not only in Washington but in legislatures and statehouses around the country, which also have a significant impact on people’s lives. Trende and Byler conclude that the Republican Party is already stronger than it has been for many decades. With a good result in 2016, including a takeover of the White House, it could virtually sweep the board. Indeed, Trende and Byler say, the Republicans could end up in their strongest position since 1920, the year women got the vote.

If the spectre of today’s Republican Party monopolizing most of the levers of power at the federal, congressional, and state levels isn’t enough to get people exercised about 2016, I don’t know what is. From tax and spending policy to health insurance, foreign policy, and social issues like gun control and gay marriage, the country would be subjected to a concerted effort to roll back time. While the Senate filibuster and the courts might exercise some restraint on the G.O.P. victors, many members of the Party would be determined to use their position of dominance to set the country on a regressive, rightward path.

Is this too alarmist? One can quibble with the power index that Trende and Byler constructed to gauge the political influence of each party, which consists of five equally weighted parts: Presidential performance, House of Representatives performance, U.S. Senate performance, gubernatorial performance, and state legislative performance. (“Performance” refers to measures of electoral performance, rather than of governance.) Perhaps the Presidency should be assigned more importance than the national and local legislatures. Another pertinent criticism is that the two analysts don’t weight state governorships by population, which means, for example, that the victory of a Republican governor in Arkansas counts for as much as that of a Democratic governor in California.

Still, the Trende and Byler power index has the merit of being straightforward, and it enables the analysis to be taken all the way back to the Civil War. In 1866, Lincoln’s G.O.P. scored a hundred and eight, a number it has never again attained. The Republicans’ worst ever score was recorded after the Roosevelt landslide of 1936: minus a hundred and nineteen. (A negative score for one party implies a positive score for the other.)

For much of the postwar period, the Democrats held a narrow lead over the Republicans on the power index, but this changed after the 2014 midterms, when the G.O.P. score jumped up to 33.8. The fifty-four seats the Republicans won in the Senate was their second-best result since 1928, and the two hundred and forty-seven seats they hold in the House is the highest since after the 1928 election, when Herbert Hoover trounced Al Smith. At the local level, the G.O.P. now has thirty-one governors, and it controls sixty-eight of ninety-eight partisan state legislatures, its best showing since 1920.

Trende and Byler concede that their portrait of Republican dominance “is at odds with the prevailing theme of a Republican Party with serious demographic problems,” which “make it difficult for the GOP to win the presidency.” But they also point out that “those same shifts have strengthened it in the states, which is where most lawmaking takes place.” (In an earlier article, Byler pointed out how partisan redistricting has also helped Republicans at the local level.) The two analysts conclude: “None of this is to say that Republicans are building a permanent majority of any sort. It is simply to say that when one takes account of the full political picture, the Republican Party is stronger than it has been in most of our readers’ lifetimes. This is important, and more analysis should take account of this fact.”

It should—and indignant voters should pay attention, too. At this stage, Democratic control of the White House is about the only thing holding the Republicans back, but they are far from invulnerable. Thanks to the big gains they made in the midterms of 2010 and 2014, they will be defending a lot of seats at the national and state level that are potentially up for grabs. Indeed, Trende and Byler note that, “a bad Republican year could place the party ‘in the red,’ with its share of the presidential vote, Senate, House and state legislatures falling precipitously.” In short, the 2016 election could bring a quick end to Republican gains, or it could assign the G.O.P. a position of dominance. It matters; it matters enormously.