For months now, Donald Trump has suggested that his position on trade will help him win over Sen. Bernie Sanders’s voters in the presidential election. The presumptive GOP nominee even implied that support from Sanders voters could offset a potentially divided Republican Party, saying recently, “I’m gonna get Bernie people to vote, because they like me on trade.”

That almost certainly won’t happen. “Bernie people,” for starters, do not agree with Trump on trade. A Pew Research Center survey in March found that Sanders supporters look much more like rival Democratic candidate Hillary Clinton’s voters than Trump’s on trade. Only 27 percent of Trump supporters in the Pew poll said that free trade is good for the United States, compared with 55 percent for Sanders supporters and 58 percent for Clinton voters.

Perhaps more important, opinions about free trade are entirely unrelated to Sanders supporters’ vote preferences in a Trump vs. Clinton match-up:

The graph above, which uses data from the March wave of RAND’s Presidential Election Panel Survey (PEPS), shows that Sanders supporters are unlikely to support Trump regardless of whether they think trade leads to better products in the United States.

Now, there is one issue that does lead Sanders supporters to defect to Trump: immigration. The graph below shows that Sanders voters who agree with Trump’s highly visible positions on a border wall and mass deportation are more likely to support Trump against Clinton.  This is true even after accounting for several other factors.

The problem for Trump, however, is that not many Sanders supporters share his immigration positions. The numbers at the bottom of the figure indicate that Sanders voters overwhelmingly disagree with Trump’s positions. Recent surveys by Pew and YouGov similarly show that Sanders supporters are very liberal on immigration issues.

It’s not only immigration and trade where Sanders supporters are closer to Clinton than to Trump.

The graph above shows the average positions of Trump, Clinton and Sanders supporters on scales that capture immigration issues (border wall and path to citizenship), economic issues (minimum wage, taxes, government health care and unions), social issues (abortion and same-sex marriage), gun control (assault weapons ban) and environmental issues (regulations to curb climate change and the Keystone pipeline).

Sanders supporters are much more liberal than Trump voters on all of these issues. They look an awful lot like Clinton supporters. Or, as Clinton has repeatedly told Sanders supporters in recent weeks, “there is much more that unites us than divides us.”

These similarities between Sanders and Clinton are likely to become more salient over the next five months. A long line of political science research shows that disaffected partisans increasingly support their party’s nominee over the course of the campaign. This “partisan activation” occurred in 2008 and 2012, as partisans who were initially hesitant to support John McCain, Barack Obama and Mitt Romney overwhelmingly voted for them in the general election.

Of course, things could be different for Trump. But the historic pattern of partisan activation, combined with the results above, suggests that Trump should not count on winning many Sanders voters in November. And he shouldn’t expect his position on trade to help him pull off such an improbable feat.

Michael Tesler is assistant professor of political science at the University of California at Irvine and author of “Post-Racial or Most-Racial? Race and Politics in the Obama Era.