Timothy Stafford is a Research Fellow with Pacific Forum-CSIS, and a former Parliamentary Researcher to Sir Malcolm Rifkind.

Tomorrow, Donald Trump will be sworn in as the American President. Not only is that a statement most people never expected to read, but for some, its statement they’re not prepared to accept.

Since November, Trump rejectionism has snowballed. Over 60 House Democrats are now set to skip the inaugural festivities, as part of a growing campaign to deny Trump the legitimacy that attends the office he is about to enter. Indeed, Trump’s latest twitter-spat with Congressman John Lewis began when the noted noted civil rights activist referred to Trump as ‘illegitimate’, comments the New York Times’ Paul Krugman described as ‘an act of patriotism’.

As Washington Post columnist Charles Krauthammer noted, Trump’s opponents have spent recent weeks “pushing one line after another to delegitimize the election, as in: he lost the popular vote, it’s James Comey’s fault, the Russians did it”.

At its core, the illegitimacy argument rests on the notion that Trump’s Presidency is an unprecedented aberration. For many commentators, this is a given. Jonathan Freedland at the Guardian captures the mood perfectly: “there is no precedent to guide the media or policymakers, because there has been no US president remotely comparable to Trump”.

Suggestions such as these not offer no credible road map for dealing with the reality of a Trump Presidency. They also betray a woeful disregard for American history. One doesn’t have to welcome the dawning age of Trump to note that the current moment has plenty of historical parallels.

As Theresa May prepares for her first bilateral meeting with the new President, she should keep four in mind.

The new Jackson:

In the earliest days of the United States, elite legislators steered the Electoral College votes of their states towards well-established figures. Yet by the 1820s, this system had all but collapsed, due to the elimination of property owning restrictions and western migration.

The result was a truly democratic exercise that benefitted a man who horrified the elites of both parties: Andrew Jackson, the former general known as ‘old Hickory’ for having survived being shot in a duel.

Jackson’s contempt for Washington new no bounds. Having been swindled out of the Presidency (as he saw it) in 1824 as a result of a ‘corrupt bargain’ between rivals, he swept into office with a significant congressional majority four years later. So enthusiastic were his supporters that they stormed the White House itself on Inauguration Day, damaging much of the property.

Once in office, Jackson trashed sacred cows of the existing order, vetoing the renewal of the National Bank, threatening the use of military force against states which defied him, and inflicting brutal punishments upon Native Americans. Above all, he brought an end to politics as an elite affair, ushering in an era of raucous mass democracy.

No other President offers a better model for what to expect from Trump: a man lifted to office by a qualitative change in the way voters participate in the political system, and who intends to govern by anti-establishment sentiment.

Polk Redux:

James K. Polk entered office in 1845 as a Jackson protégé, in an election defined by whether or not to admit Texas, newly independent from Mexico, into the Union.

Polk was an outsider whose candidacy never seemed serious. Yet triumphing, largely on his support for annexation, he used his Presidency not only to incorporate Texas but to sweep away Mexican control of the entire West. Within four years vast tracts of land, including all of today’s South West and California, had been acquired.

Trump enters office with far less grandiose plans. Yet his disdain for Mexico – both for its opposition to his plan to build a wall across the southern border, and his belief that trade with America’s southern neighbor is a job-killer – would come as no surprise to the 11th President.

The Ghost of Nixon:

In some ways, the secretiveness of Richard Nixon seems to stand in complete contrast to Trump, whose obsession with media coverage knows no bounds. Yet in terms of their personalities, there is much that links the two men.

The first is their sense that the ‘powers that be’ are against them. Even once he’d risen to the Presidency, Nixon harboured a lifelong grievance against the liberal intelligentsia. To listen to Nixon’s recordings of his oval office deliberations is to discover a man frequently engaging in talk more akin to that of conspiracy theorist.

Trump, who has continually felt ostracized from Manhattan society, is cut from the same cloth. His suggestion that the election would be ‘rigged’ against him is likely to foreshadow similar acts of paranoia once in office.

Likewise, the two men share a willingness to set aside support for democracy as a focus of US foreign policy. In the minds of both, politics is a dirty sport, in which cutting deals is the only surefire way to come out ahead. Look for Trump and his team to adopt Nixon’s outreach to China as their playbook for approaching Russia.

An Eisenhower Republican:

Few would compare Trump to Dwight Eisenhower, the calm and internationalist commander of the D-Day landings at Normandy. Yet it is worth remembering that in the early 1950s, having been out of power for two decades, the Republican Party at large was still committed to repealing most of the New Deal programs pioneered by Franklin Roosevelt.

Eisenhower’s decision to seek the 1952 nomination led to a fight – pitting moderation against the small-government reactionaries arrayed around Robert Taft. Just as it took Tony Blair to consolidate the reforms of Margaret Thatcher, so it took Eisenhower to consolidate the welfare state enlargements of his Democratic predecessors.

In Trump, the Republicans have nominated a man who is, on a whole host of issues, more moderate than they are. Its hard to imagine many other Republican holding a pride flag, vowing to protect Social Security, or moving to defend the insurance afforded to lower-income Americans by Obamacare.

So, as was true under Eisenhower, don’t expect wholesale conservative policy change in Washington.

Trump the populist, Trump the belligerent, Trump the paranoid, and Trump the moderate. Whatever the next four years holds, America has seen it all before.