President Trump has had a tumultuous two years in office, but as he starts to ramp up his reelection campaign, he can boast of having presided over the lowest recorded average unemployment rate of any of his predecessors at this point in their presidencies.

On Friday, the Bureau of Labor Statistics reported that the unemployment rate had held steady at 3.8%. That brings the average unemployment rate for the first 26 months of Trump's presidency, from February 2017 through March 2019, to 4.1%.

Starting with the presidency of Dwight D. Eisenhower in 1953, there has never been a president who oversaw such a robust employment market at this point in his presidency. This is demonstrated in the chart below. The official BLS unemployment data go back to 1948, and thus is not available for the comparable period in the Harry S. Truman era or earlier.

To be sure, there are limitations to this analysis. Often presidents are elected in times of economic peril, and thus inherit high unemployment rates, which go down over the course of their presidencies. This was the case with Ronald Reagan and Barack Obama. In contrast, Trump inherited an economy that had already been on the mend.

Should the job market remain strong, a big part of the debate in the 2020 elections will likely hinge on this point — whether Trump's tax and regulatory policies helped drive down unemployment to historically low levels, or if Obama deserves more of the credit.

Either way, if things keep up, it will complicate efforts by Democrats to make the economic case against Trump. Between February 1970 and the start of the Trump administration, there had only been five months in which the unemployment rate had been under 4% — all during 2000, just before the fallout from the bursting of the dot-com bubble. Yet in 10 of the last 12 months, unemployment has been sub-4%. Not since 1969 has there been a year with consistently lower unemployment.

The strong economic performance will also be a test of a lot of models predicting the outcome of elections. Many analysts rely heavily on the state of the economy when predicting whether an incumbent will get reelected. However, typically, when the economy is strong, it is also associated with a solid presidential approval rating. Yet Trump has polled consistently lower than other presidents, despite the strong economy.

For instance, take Eisenhower and Richard Nixon, whose unemployment rates came closest to Trump, at 4.4% and 4.5%, respectively. At the comparable points in their presidencies, according to Gallup, Eisenhower was polling at 71 percent and Nixon, while less popular, was still at 50%. In contrast, Trump is currently polling at 39%.

That's why predicting the 2020 election is so perilous, especially with the Democratic nomination battle so wide open. It's easy to come up with a scenario in which Trump loses reelection despite having the strongest presidential term for employment in recorded history, because he turns off voters in many other ways. On the other hand, it's also possible to imagine an outcome in which the strength of the economy convinces voters to get past their objections with Trump and stay the course rather than risk radical change being promised by Democrats.