It's a widely accepted truth of the Donald Trump era: The US President deliberately divides Americans on issues like immigration and often employs controversial rhetoric, but he's doing it because it works! It's his secret political genius!

What if it doesn't, though, and what if it's not?

Elections are so infrequent and there are so many variables that it's very difficult to completely isolate one of them and render a verdict on its impact.

Because Trump won in 2016 and because culturally conservative, blue-leaning states along the Rust Belt cast the decisive votes, it's not difficult to draw a line between Trump's historically tough immigration rhetoric and his victory.


And there's a real argument to be made today that turbocharging the immigration debate in the final days of the 2018 Midterm campaign furthers Trump's and the GOP's goal of energising a previously unenthusiastic base.

Throwing this on top of Brett Kavanaugh's Supreme Court nomination would seem to do the trick - particularly when it comes to winning the red states required to keep the Senate.

But, as Republican pollster Glen Bolger often reminds us, enthusiasm is only part of the battle. And the Senate is only half the battle.

There is also real reason to believe what Trump is doing now could alienate independent voters and maybe even hurt the GOP's efforts to keep the House.

The battleground there, after all, is in red-but-not-quite-so-red territory, and some polls suggests independents and those crucial areas aren't so fond of Trump's hardline immigration stance.

"I would not assume that it's a positive or a negative," Bolger said. "This is one of those things where we're a heck of a lot smarter at midnight or 2 am on election night."

The most recent Washington Post-ABC News poll this month showed independent voters favoured the Democratic Party 48 per cent to 32 per cent when it comes to handling immigration. That's an almost complete reversal from in 2015, when independents favoured Republicans 43 per cent to 27 per cent.

Similarly, a July Washington Post-Schar School poll of battleground congressional districts showed those districts disapproved of Trump's handling of immigration by 58 per cent to 41 per cent. Independents nationwide overwhelmingly disapproved of Trump on immigration, 63 per cent to 37 per cent.


Polling has regularly shown Americans strongly oppose Trump's border wall, overwhelmingly support the DACA policy he voided, and favour the kind of comprehensive immigration reform and path to citizenship he has eschewed.

Even Trump's latest base play - revoking birthright citizenship for the children of undocumented immigrants - had only 37 per cent support when Pew last polled it back in 2015. Support for that proposal among independents had been dropping for a decade, from 44 per cent back in 2006.

All of this comes with a caveat: Immigration as an issue often isn't so much about how people feel as it is about how strongly they feel.

Immigration hardliners are among the most passionate and mobilised people in politics (which is how they've killed off multiple popular comprehensive bills). For this to really hurt the GOP in the election - even if just in the House and not the Senate - those independent voters have to not only disapprove of Trump's immigration policy but actually vote against Republicans because of it. That's a very different question.

But Trump is also testing the bounds of how extreme one can be on immigration in a way we haven't seen from past presidents or even from Congress.

And while immigration might have helped Trump in 2016, it's also fair to note that:
- his opponent was the other most unpopular presidential candidate in modern history;
- Trump lost the popular vote;
- he won by less than 80,000 votes in the three Rust Belt states that decided the election, Michigan, Pennsylvania and Wisconsin.

He very nearly lost, at which point we'd almost undoubtedly eulogise his immigration strategy as a bust.

Oh, and also, the GOP suddenly isn't doing so well in the Midwest and Rust Belt.

Perhaps the caravan strategy and Trump's upping of the ante will help remedy that.

It's also possible that we've oversold the success of his divide-and-conquer approach on issues like immigration just because he eked out one win in some very special circumstances two years ago.

The next election may not prove it one way or another, but will at least add to the very limited data set we can use to evaluate Trump's alleged electoral genius.