As practically the whole world knows, this was the week in which Michael Cohen, Donald Trump’s former fixer, testified on Capitol Hill, and Trump returned from Hanoi empty-handed after an abortive summit with North Korea’s Kim Jong Un. But, in historical terms, this week may go down as the one in which the 2020 Presidential election started in earnest. During Cohen’s dramatic appearance Wednesday before the House Oversight Committee, and in other venues, both parties displayed the strategies they hope to use to defeat the other side.

In any Presidential race featuring an incumbent, the contest is ultimately a referendum on the performance of the sitting President, and that person typically wins. (The last President to fail to win reëlection was George H. W. Bush, in 1992.) But, of course, Trump isn’t a typical incumbent, and the Democrats are optimistic that they can deny him a second term. One way to turf him out would be for the special counsel, Robert Mueller, to submit a report to the Justice Department that is so damaging and probative it convinces enough Republicans to abandon him for an impeachment trial in the Senate to succeed. But the smart money in Washington is betting this isn’t going to happen, and the Democrats’ Plan B appears to be to torment Trump all the way to Election Day with congressional hearings of the sort we saw this week. Already, the Senate Intelligence Committee has announced plans to question Cohen again, on Wednesday, and, eight days later, to question his sidekick on the Trump Tower Moscow deal, Felix Sater, a convicted felon who once took part in a stock-fraud scheme orchestrated by mobsters.

That will only be the start. The House Intelligence Committee is planning to call many of the Trump associates whom Cohen mentioned in his testimony, including Allen Weisselberg, the chief financial officer of the Trump Organization. The House Democrats are also gearing up to look into all aspects of Trump’s record, including his other business dealings, his tax affairs, and his now defunct charitable foundation. “All you have to do is follow the transcript,” Representative Elijah E. Cummings, the chairman of the Oversight Committee, told the Washington Post. “If there were names that were mentioned, or records that were mentioned during the hearing, we want to take a look at all of that.”

“In other words,” as Jennifer Rubin, one of the Washington Post’s Never Trump conservative columnists, pointed out on Friday, “way before moving on to consider the possibility of impeachment, there will be months of hearings laying out in public potential Trump crimes and assembling a list of Trump’s lies.” And there doesn’t necessarily have to be an impeachment at the end of the road. “Democrats may be entirely content to let all of this unfold,” Rubin wrote, “leaving Trump and the GOP mortally wounded but not yet expired on Election Day 2020. It’s all upside and no downside for Democrats to proceed this way.”

That remains to be seen, of course. There were several reasons Cohen was such a compelling witness. For more than ten years, his job was to do Trump’s dirty work, which gave him unrivalled access to the seamiest side of Trump’s world. On top of this, he made a specific allegation—backed up by cancelled checks, court documents, and his own guilty pleas—that Trump directed a criminal conspiracy to violate campaign-finance laws by paying off two women with whom he had affairs: Stormy Daniels and Karen McDougal. Future witnesses may not have such explosive testimony to offer, although Cohen, in the rest of his testimony, certainly provided the Democrats with some interesting areas to pursue. For example, take Weisselberg, whom Cohen accuses of helping to disguise the payments to the lawyers representing Daniels and McDougal. And Weisselberg has been involved in many other areas of Trump’s dealings, of course. In a post on Friday, my colleague Adam Davidson listed fifteen questions that the House Democrats might want to ask him.

In the face of the coming Democratic onslaught, the President and his Republican allies will follow a two-part strategy, which they showcased this week in their response to Cohen’s testimony. The first part will be to try to discredit anyone who says anything negative about Trump and to portray the Democratic investigations as partisan overkill. “This is Step One in the Democrats’ crazy efforts to impeach the President of the United States,” Jim Jordan, the ranking Republican on the House Oversight Committee, said Thursday, in a speech at CPAC, the annual conservative gathering in Washington. “And the best they could come up with is this guy who is going to prison in two months for lying to Congress.”

If you think this sort of positioning is rich for a party that had six committees to investigate the Benghazi attack, and allowed the probes to drag on for more than four years even though they didn’t turn up very much, you are right. But that won’t stop the House Republicans. They are cynical to the bone. And they know that, partly as a result of their own ridiculous antics, Congress has a low job-approval rating—lower even than Trump’s. So they will try to exploit this to the President’s advantage.

In addition to conducting this type of rearguard action, Trump and the Republicans will also go on the attack, seeking to portray the Democratic Party leadership and its Presidential candidates as the captives of left-wing radicals such as Alexandria Ocasio-Cortez, the first-term congresswoman. This tactic was also on display at the CPAC conference, which on Friday featured a panel session titled “AOC’s Green New Deal: Debunking the Climate Alarmism Behind Bringing Full Socialism to America.” In an interview on the eve of the conference, its host, Matt Schlapp, the chairman of the American Conservative Union, said, “When the American people see the radical policies Democrats have added to the agenda, it gives Republicans a great opening.” Evidently, many of the conference speakers agree with Schlapp. Mark Meadows, the head of the House Freedom Caucus, accused Ocasio-Cortez of “embracing socialism”—a cardinal sin, apparently. Sebastian Gorka, the odious former White House aide, declared, “What is America’s biggest problem? Not socialism in Russia but in America!”

With Trump’s approval ratings still languishing in the low forties, it would be easy to dismiss this Republican strategy as desperate posturing that is unlikely to convince Americans to support the embattled President come November of next year. Many of the policies that leftist Democrats like Ocasio-Cortez and Bernie Sanders are pushing, such as aggressively tackling climate change, raising the minimum wage, and pushing for universal health-care coverage, are popular with voters, according to opinion surveys. But the anxious signals being emitted by some moderate Democrats in Congress will give the G.O.P. strategists hope that all is not entirely lost. In a closed-door meeting on Thursday, Ocasio-Cortez and some Democrats elected from purple districts clashed verbally after the New York firebrand objected to some moderates breaking with the Party in a gun-control vote. Representative Xochitl Torres Small, who won election last November from New Mexico’s Second District, “reacted sharply to Ocasio-Cortez’s comments and rose to urge her colleagues to respect the political reality of representing a swing district, according to multiple people present,” the Washington Post reported on Friday.

In the months ahead, Trump and his Republican colleagues will be looking to exploit these sorts of tensions and make life difficult for the Democratic Presidential candidates. The Democrats on Capitol Hill, meanwhile, will be doing their utmost to insure that Trump, even if he survives the threat of impeachment, remains unpopular and vulnerable. Policies will matter as well, of course. But this week we got a glimpse of how the two parties’ over-all battle strategies are shaping up.