2018 offers hints at disruptions on road to 2020: ANALYSIS The 2020 elections will likely yield partisan drama and divisions.

The political system was shaken up yet again in 2018, with midterm elections and congressional dysfunction that reflect the anger and divisiveness of the times.

Yet for all the wild turns politics took in the first two years of President Donald Trump’s tenure in office, they offer only hints at the drama and divisions that figure to dominate the next two.

Here are some of the major fights to look out for inside and between the major political parties in the run-up to 2020.

Diverse crop of Democrats will vie for Oval Office

Congressional leaders will begin to assert newfound authority in the House come January, bringing fresh scrutiny to the White House and putting pressure on Democrats to develop an agenda that is more than just opposing Trump.

That won’t even be the main event -- not even close. A record-breaking field of presidential contenders are set to vie for the right to take on a president the party desperately wants to defeat.

Democratic debate stages in 2019 and early 2020 are likely to be populated by more women than have ever run before, as well as multiple black and Latino candidates.

The field could include some of the most and least experienced candidates for the presidency, as well as some of the youngest, the oldest and the wealthiest -- even compared to the current president.

Their disputes will be ideological, of course. But more than that, the candidates are likely to argue over attitudinal and generational lines, with memories still fresh of the bruising 2016 primaries and the bitter disappointment of Hillary Clinton’s loss.

Democrats have found a large measure of unity in opposing Trump. But that sense of shared purpose is likely to become splintered as candidates ranging in age from their mid-40s to their late 70s argue over how best to both stand up to the current president while offering a vision for the next presidency.

Rough road ahead for Republicans

Even by Trump’s standards, this is likely to be a rocky stretch for the president and his party.

The GOP will have to adjust to life in the minority in the House. The White House will have to adjust to the reality that no legislation will advance without the support of the new Democratic majority.

There will be much that no one in the party can truly control. A shaky economy and tenuous relations with friends and allies -- to say nothing of China, Russia, Iran, Saudi Arabia and North Korea -- could force Republicans to confront fissures in their ranks.

Special counsel Robert Mueller’s probe hangs over all. Trump has been able to count on general support from Republicans in Congress even as legal clouds around his presidency grow, but that could change depending on prosecutors’ next moves.

The president’s popularity inside his own party would, in normal times, insulate him from the worry of primary challenges, or of a serious third-party threat.

Yet Trump’s erratic behavior and potential entanglement in federal criminal probes mean both of those avenues are real possibilities for the first time in a quarter century.

The next seasons of the reality show that is the Trump presidency will feature transitions and big gambles. One major calculation for Republicans will be how to calculate what support to offer for a president who could be facing growing political and legal pressures.

External factors will test the power of incumbency

A slowing economy, a quickening series of overlapping investigations, and a new dynamic of Democrats with subpoena and oversight power mean new political challenges in the new year.

More broadly, both Democrats and Republicans will face growing tensions over their core identities. Powerful demographic and institutional forces will play out against the backdrop of substantial governing challenges.

The path ahead will offer reminders of how Trump essentially broke both parties in his unlikely 2016 triumph. Neither party has put the pieces back together in time for 2020.

And -- adding a new element to campaign politics -- a president who never stopped campaigning will be live-tweeting it all, even as his presidency faces the potential of growing threats from multiple directions.

If a wave crashed this past year, no calm is in the forecast from here.