A Democrat presidential fails to succeed a popular two-term incumbent president from the same party, despite low unemployment, an opponent who appears out of his depth, and, oddly enough, winning the most votes on Election Day.

I’m not only talking about Hillary Clinton, but also Al Gore.

Their inability to protect the Oval Office raises a big question for Democrats: Can they win the White House without a charismatic outsider for a nominee and without a Republican-made mess to clean up? Because neither of those factors is always easy to come by.

No Democrat has been able to take the baton and keep party control of White House for a third term since Martin Van Buren in 1836, and he had the advantage of running against a Whig party that failed to agree on a single nominee. Since then, only Franklin Delano Roosevelt was able to win a third consecutive term for the Democrats, but he had the luxury of finishing what he started. (Republicans have had a slightly easier time stringing together three or more consecutive terms, accomplishing the feat four times since the party’s founding 162 years ago.)

So this is not a new problem, but the reasons for the most recent defeats diverge from the problems of the more distant past.

Before Gore and Clinton, blame for failing to piece together winning streaks landed squarely on the incumbent Democratic presidents. The 1920 nominee, James Cox, had no shot after Woodrow Wilson waged the unsuccessful fight to join the League of Nations, while neglecting the turbulent transition to a post-war economy. In 1968, Hubert Humphrey had the thankless task of trying to unite a party shattered by Lyndon Johnson’s war in Vietnam.

The Gore and Clinton autopsies are more complicated. They were felled by similar weaknesses. Both were ensnared in arguably small-bore ethical scrapes that became overheated in the campaign crucible. And both suffered late hits from external forces. Gore was ultimately defeated by the Supreme Court. Clinton had to fend off Russia, WikiLeaks and the FBI.

But most importantly, both were technocrats who sought to sell their policy smarts rather than try to make an emotional connection to the electorate, while being juxtaposed with incumbents who made connecting look effortless. Without that connection, attacks on character and integrity are much harder to overcome.

This is not just a matter of personality type, but political timing. When you are trying to extend a streak, you are, by definition, running as a representative of the existing Establishment, a far less exciting and inspiring task than running as a fresh-faced agent of change.

You can try to strike a populist note, as Gore (“they're for the powerful; we're for the people”) and Clinton (“the deck is stacked in favor of those at the top”) tried to do. You can try to emphasize certain differences between yourself and the incumbent. But there’s no getting around the fact that you supported the policies of the past eight years, and, if not literally promising status quo, would govern in a similar vein.

If the electorate were ever firmly on the side of the ruling party, such a “stay the course” message would be sufficient. But voters have a tendency of being nonplused by political achievements. When you consider that Prime Minister Winston Churchill was cast off by British voters two months after Germany was defeated in World War II, it makes one better understand Gore’s difficulty in running on Bill Clinton’s balanced budgets or Hillary Clinton’s challenge in touting Barack Obama’s steady job growth.

It’s unusual for a ruling party to have a sweeping and unequivocal success that can solidify its bond with a sizable majority. Typically, policy advancements are incremental, and their positive impact is unevenly distributed. For example, Hillary Clinton celebrated that 20 million more people have health insurance thanks to Obamacare, the incumbent’s signature domestic achievement. That’s a big number, but the electorate was more than six times bigger. Moreover, others who previously had insurance and saw their premium rise won’t appreciate that the rise might have been higher without Obamacare. In turn, support for Obamacare in the 2016 election was split down the middle, almost perfectly tracking the national popular vote.

The problem of lingering dissatisfaction with incremental change is a major obstacle for ruling parties, but especially Democrats. As the party of activist government, the Democratic Party tends to be judged primarily on the scope of its domestic policy performance. If Democrats can’t condition voters to accept a realistic pace of change, the boom-bust cycle of initial hope followed by crushing disappointment is bound to bedevil them.

As Democrats will suddenly control no branch of the federal government, solving the puzzle of how to win a third term in a row is probably low on their list of priorities. But if they are to have an opening to wrest the White House back from Trump in 2020, it will probably be because Trump failed to meet the outsized expectations he gave himself. When Democrats look to seize any such opening, they may want to be careful not to overpromise all over again.