It should come as something less than a shock that the United States is watching closely — and in some quarters, nervously — as Canada’s new government moves with bold, audacious speed on Syrian refugees.

Fear of the Canadian border as a gateway for terror — a recurring theme in U.S. politics since the attacks of 9/11, despite all evidence to the contrary — appears to be stirring anew as the sheer heft of the Canadian plan takes shape, with expectations of as many as 1,000 refugees a day arriving in Canada starting Dec. 1.

A telltale clue on the jittery thinking among U.S. officials came even before Friday’s attacks in Paris, when a senior officer with the U.S. embassy in Ottawa was overheard at a public gathering on Remembrance Day bluntly discussing Washington’s anxieties that some among the 25,000 refugees may come intending to travel south and wreak American havoc, ISIS-style.

“The message was very clear and not couched in diplomatic language — I heard, ‘My government is highly concerned’ about the potential threat at the border,” a witness to the U.S. official’s remarks told the Star on condition of anonymity. The official in question, Peter Malecha, a first secretary at the embassy, did not respond to the Star’s request for comment.

It is unclear whether it’s the speed or size of Ottawa’s refugee mobilization — or perhaps both — that rankles most. Either way, the fact that Canada is about to punch far above America’s weight on Syrian refugees is not going unnoticed. The Canadian pledge to absorb 25,000 people by year’s end vastly overshadows anything contemplated in Washington, where officials are looking at opening the door to an additional 10,000 refugees by the end of 2016. In per capita terms, Canada’s target is 25 times more generous than what Washington envisions. And it will happen 12 times faster.

Close watchers of the Canada-U.S. file in Washington say they are unsurprised by the added U.S. scrutiny, given how border security dominates American political conversation. Unlike in Canada, the Syrian refugee debate south of the border has been subsumed into the already overheated political battle over immigration, with Republican frontrunner Donald Trump warning any large influx of refugees represents a “Trojan Horse” security threat.

“These kinds of American anxieties speak to the borders-first mindset that prevails. And at the same time, Ottawa is being watched down here because it is not just a new government but a young government,” said Washington consultant Paul Frazer, a former Canadian diplomat specializing in cross-border issues.

“At the same time we need to keep in mind that we are a long way from 9/11 and the enhancements in border security have grown year after year, with an array of protections, coming and going. Is it presumptuous to sound the alarm about 25,000 people when Germany is dealing with 700,000 refugees as we speak? It probably is.”

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