Until 2016, Ohio was the ground zero of presidential politics. Yes, there was also Florida, Ohio's bookend in all recent elections. But the Buckeye State's fiercely competitive environment, combined with its heartland sensibilities, often made it the nation's preeminent political crossroads every four years.

Everyone assumed 2016 would produce another memorable struggle, this time between Donald Trump and Hillary Clinton. But as with so much else in the campaign, Trump tossed aside the expected script, as he swept to a surprisingly easy victor. Trump won all but eight counties, the best for any Republican since Ronald Reagan in his 1984 landslide - and Reagan carried the state by 19 points.

Michael Dawson, an expert on Ohio election statistics, offered other examples of the breadth of Trump's victory. The president ranked in the top 10 of best-ever Republican performances in 61 of Ohio's 88 counties. In 38 counties, he had the best percentage of any Republican nominee dating back 10 elections. His victory margin in northwest Ohio was third best of any Republican ever. And with his America First message, he lost heavily Democratic northeast Ohio by the second smallest percentage of any Republican nominee.

Trump has turned the state's Republican Party upside down, which has left Republican Gov. John Kasich almost a man without a party in his own state. Kasich, of course, lost the GOP nomination to Trump in 2016, boycotted the arena at the GOP convention in Cleveland and ever since has been a critic of the president - and a possible 2020 challenger.

The contours of Ohio's new politics will be on national display over the coming days, beginning with the president's Saturday visit to Cleveland. The trip comes at the end of a week of controversy for the president that, if his appearance at the National Rifle Association on Friday is any indication, has only hardened the support among his base.

His visit comes on the eve of Tuesday's primary elections, in which the president is more than a bit player. The ultimate answer as to how Trump has changed the politics of the state will come in 2020, if he is on the ballot. But some clues will emerge from this year's midterm elections, with Tuesday's primaries providing the first indicators.

Kasich, who is term-limited, will be stepping down after eight years as governor. When he leaves office, Republicans will have held the governorship for 24 of the past 28 years, the lone break coming when Ted Strickland rode the 2006 Democratic wave to victory, only to be rejected by the voters when he faced Kasich in the big GOP tsunami of 2010.

Winning governorships is essential for Democrats if they hope to rebuild their party nationally. Ohio will present a major opportunity and a major challenge for the party in 2018. The Democratic primary reflects some of the fissures and tensions inside a party that has moved left and is debating just how far left is should go.

The primary features two former elected officials. The front-runner is Richard Cordray, who served as state attorney general and most recently led the Consumer Financial Protection Bureau (CFPB) in Washington. He is a Democrat at least partially in the mold of Sen. Elizabeth Warren, D-Mass., who led the fight to create the CFPB. He is consumer oriented and a bane of Wall Street and big banks.

He is described as part of the party's progressive wing, and on those kinds of Wall Street issues, that's certainly correct. But on gun issues, for example, he is more moderate than many progressives. When he ran for re-election in 2010, he had an A rating from the National Rifle Association. His current rating is C-minus.

Though an ally of Warren on many issues, he lacks the Massachusetts senator's energy and passion and has been tagged with running a colorless campaign. A cartoon in the Cleveland Plain Dealer on Friday showed a Cordray caricature wearing a red cap that read, "Make Ohio Bland Again."

His principal opponent is a familiar figure in the state and nationally: Dennis Kucinich, the former Cleveland mayor, former Congress member and former presidential candidate. He has long operated on the party's left edge, and in this contest, that's where he has planted his flag. He has support from some of those Democrats who backed Sen. Bernie Sanders, I-Vt., for president in 2016.

Two factors threaten to hold down his vote, however. First is his lack of money, which has made it difficult for him to run television ads that could expand his appeal beyond his northeast Ohio base. Second and more significant was the embarrassment of having accepted $20,000 for a speech he gave to a group that included an organization sympathetic to Syrian President Bashar al-Assad. Kucinich announced that he would return the money, but past links to Assad have dogged him in the campaign against Cordray.

Democrats will be paying close attention to two things Tuesday. First is the Kucinich vote and what it says about the power of the left within the party. Second will be overall Democratic turnout, compared to that of the Republicans. Early voting has shown Democrats with an advantage, but Republicans expect the overall vote to look different after Tuesday's balloting. Democrats won't win in November without a truly energized base.

The Republican primary pits Mike DeWine, the current state attorney general and former U.S. senator, against Mary Taylor, the state's lieutenant governor. Notably, neither has sought the Kasich mantle in their campaigns. DeWine doesn't particularly need it, given strong statewide identification and a record of his own. But it is more telling that Taylor, who was elected lieutenant governor on a ticket with Kasich, has also run away from him — sometimes quite awkwardly.

Taylor has sought to embrace Trump and cast DeWine as an establishment Republican. DeWine has tried to deflect those attacks by questioning whether she really supported Trump in the fall of 2016. But he is also mindful that he will need the support of Ohio Republicans and independents who don't like the president to win the general election in November, if he wins the nomination on Tuesday.

DeWine is the favorite heading into Tuesday. His allies are confident of victory. If the primary turns out to be close, Taylor's performance would be a sign of Trump's influence among rank-and-file Republicans, and, if DeWine is the nominee, make the political balancing act more challenging.

The other primary drawing real attention is the contest for the GOP nomination in the 12th Congressional District, a seat left open by the resignation of Republican Rep. Patrick Tiberi. The contest pits Troy Balderson, who is Tiberi's choice, against Melanie Leneghan, who is running as a proud Trump Republican. The vacancy will be filled with a general election in August and Democrats see the seat as a possible pick up, especially if Leneghan wins the nomination.

The Senate primaries hold little suspense, with Democratic Sen. Sherrod Brown and Republican Rep. James Renacci the expected general election candidates. But Brown's candidacy adds another layer to the debate over the Democrats' future. He is a populist Democrat, allied with the progressive wing and a supporter of Clinton in 2016. He has managed to navigate Ohio political terrain successfully and Democrats contemplating a presidential campaign in 2020 will be closely watching what he does this year.