Donald Trump likes Russia and Russian President Vladimir Putin, and he doesn’t try to hide it. History suggests that his affection for the country could have a significant effect on public opinion.

Over the past several presidencies, American opinion about Russia has changed rapidly based on how presidents have treated the country. During the presidencies of both George W. Bush and Barack Obama, Russia’s favorability rating rose initially as both presidents attempted public overtures to improve relations. But opinions fell steadily throughout each man’s second term after crises in U.S.-Russian relations.

These kinds of events can create short-term volatility as well as longer-term changes in U.S. public opinion of Russia (though there is not enough polling to measure Americans’ reaction to every event). For example, Russia’s favorability rating fell 11 points between February and April 1999 during tensions related to the NATO bombing campaign against Yugoslavia, and its favorability plummeted 22 points as Russia opposed the 2003 invasion of Iraq. Both of those changes were relatively short-lived, but the polling suggests that public opinion underwent more lasting changes after events like Russia’s 2008 invasion of Georgia, the granting of political asylum to Edward Snowden in 2013, and political and military intervention in Ukraine in 2014, all of which were strongly criticized by the White House.

These opinion shifts are unusual. Consider these five countries with tense or troubled relations with the United States: China, Cuba, Iran, North Korea and Pakistan. Here’s a chart with the percentage of Americans who have had a favorable view of these countries since 2000, according to Gallup polls.

The share of Americans who had a favorable opinion of Russia in that time has ranged from 24 percent to 66 percent, a span of 42 percentage points. None of the other five countries has had a range greater than 33 percentage points. The second-widest range belonged to Cuba, which became more popular after President Obama started normalizing relations with its government.

China, a major economic power that has been sharply criticized in the U.S. for its human rights record and financial practices, has had a fairly stable public image compared to Russia. Since 2000, its lowest favorable rating was 33 percent, and its highest was 48 percent.

For decades, opinions about Russia haven’t varied much by party, even during the Cold War. According to the General Social Survey, which tracked opinions on the Soviet Union (and, later, Russia) from 1974 to 1994, the percentage of Democrats and Republicans who gave the country a positive score was quite similar.

The difference between Democrats’ and Republicans’ opinion on the country was never greater than 7 percentage points, despite long Republican campaigns of anti-Communism. The same has generally been true in recent years.

But the bipartisan consensus of years past may have become less stable. The CIA has accused Russia of trying to influence the 2016 election in Trump’s favor, and Trump has been dismissive of the agency’s findings. Several Democratic officials are calling for an investigation into whether Russia interfered with the election. The result, according to one survey, is one of the largest partisan gaps in opinions on Russia in the past 40 years: In a YouGov survey conducted over the weekend, 31 percent of Republicans categorized Russia as an “ally” or as “friendly” to the United States, but only 16 percent of Democrats said the same. That 15-percentage-point gap by party is considerably wider than the 1-point gap YouGov found in late July, when 18 percent of Democrats and 17 percent of Republicans thought Russia was an ally of or friendly toward the U.S. This small difference is far more consistent with historical norms.

Opinions could swing again in the coming weeks and months, as Trump takes office and more information about possible Russian influence on the election may come to light. Some Republican leaders have joined the Democrats in calling for an investigation, and this divide in the Republican ranks may keep opinions about Russia from becoming too polarized. If Trump continues to plot his own course on Russia, it could put to the test a consensus going back decades.