Comment: How Trump planted a seed about terrorism and the migrant caravan

People line up to cross into the US from Tijuana, Mexico, seen through barriers topped with concertina wire at the San Ysidro port of entry in San Diego. Photo / AP

US President Donald Trump's closing argument in the 2018 Midterms campaign was all about fear.

The fear that a caravan of migrants coming up from Central America was so dangerous that it warranted the deployment of thousands of troops.

He even suggested there were terrorists in it.

None of this was backed up by the facts. But Republicans bought it anyway.

A new Monmouth University poll shows that nearly three-fourths (72 per cent) of Republicans regard the caravan, which still has yet to arrive, as a threat to the United States. More than half (54 per cent) regard it as a "major" threat.

But the full extent of the GOP's embrace Trump's fearmongering came in a later question.

Monmouth asked whether people believed that there were terrorists in the caravan - a suggestion that Trump made and then admitted he had no real evidence of.

Despite Trump seeming to back off it, 47 per cent of Republicans believe there are terrorists in the caravan.

And when pressed, another 16 per cent suggest it was more likely than not.

That's nearly two-thirds of Republicans who think the caravan includes terrorists seeking to do the US harm.

On October 22, Trump tweeted: "Sadly, it looks like Mexico's Police and Military are unable to stop the Caravan heading to the Southern Border of the United States. Criminals and unknown Middle Easterners are mixed in. I have alerted Border Patrol and Military that this is a National Emergy. Must change laws!"

There is simply no evidence for this, and the evidence the Administration has pointed to actually paints the opposite picture.

When asked late in the 2018 election campabout Trump's claim, Vice-President Mike Pence alleged that, "In the last fiscal year, we apprehended more than 10 terrorists or suspected terrorists per day at our Southern border."

That was false. In fact, the Department of Homeland Security says 10 suspected terrorists are denied entry to the United States at all ports of entry - not just the Southern border.

New @wesleysmorgan SCOOP: The Pentagon is set to begin a drawdown of its 5,800 troops from the Southwest border as early as this week, the Army commander overseeing the mission told POLITICO. https://t.co/YIhmCie3zk via @politico

— Carrie Budoff Brown (@cbudoffbrown) November 19, 2018

The State Department said in mid-2017 that there was "no credible information that any member of a terrorist group has travelled through Mexico to gain access to the United States".

Anonymous administration officials have said Trump's suggestion is baseless. And the last caravan included few illegal border-crossers; most legally requested asylum.

Shortly after Pence's comments, Trump himself seemed to admit he was just speculating - that the vast resources at his disposal as president had never actually substantiated his claim.

"They could very well be," Trump said of terrorists in the caravan. "There's no proof of anything. There's no proof of anything. But they could very well be."

Here's the thing that might get lost in all of this: Trump never actually said there were terrorists in the caravan.

All he had to do was suggest it was possible, and now nearly two-thirds of Republicans believe it.

Trump's tweet above makes reference to "unknown Middle Easterners" in the caravan.

He planted that seed knowing it would be interpreted as potential terrorists.

That's how Pence seemed to take it and how journalists had to take it. By the time Trump admitted he had no actual evidence, that seed had germinated.

This is how Trump spreads conspiracy theories: By saying something that is difficult to disprove and may carry a whiff of truth, but which points a blinking red arrow at what Trump is really trying to say.

Often that blinking red arrow points at something Republicans are anxious to believe - in this case, that migrants can be dangerous.

Even when the media fact check it and Trump admits he's spewing baseless allegations, it's too late. And in many ways, the fact-checking only makes Trump's followers more likely to buy into his innuendo.

It seemed to have the desired impact on the 2018 election - at least in red-state Senate races - but it's a hell of a way to do business as a government.