A border has been put in Irish Sea in part because there was no fear of violence

The DUP is right to emphahsise that point.

Mr Varadkar showed European leaders a picture of a customs post that was attacked during the Troubles.

Britain, as ever, was too diplomatic to point out that the border was once unsafe because of IRA terror, carried out by killers who used the Republic of Ireland as a safe haven.

The UK was too diplomatic to point out the same to Donald Trump when Mr Varadkar, ludicrously, implied that President Trump supported the Irish border backstop.

Meanwhile, the PSNI has at times seemed to come close to citing the potential problems at the border in ways that opponents of Brexit could make political capital.

If the border has to be policed more rigorously due to dissident violence, so be it. The security forces have a job to do and will be given every support by the government to do it in those circumstances.

As Mrs Foster says, it is hardly surprising if loyalists note with fury comments that could be interpreted as pandering to dissident thugs.

And while loyalist violence would clearly be wrong, events have been all the more frustrating for the vast majority of unionists to watch,because they threaten nothing.

As a result of this, the Irish Sea border is politically easier, and is the one London has chosen.