Donald Trump is exploiting the Orlando nightclub shooting before the crime scene has even been cleared

There have been always been two largely unspoken fears about the run-up to November's US Presidential election. Firstly, that lone wolf terrorists would strike within the United States; secondly, that it would be quickly exploited by the campaign of Donald Trump.

Both have happened. The horror of Orlando is on a truly awful scale - the worst mass shooting in American history.

And less than twelve hours later there was this tweet by Donald Trump - remarkably ill-judged and in poor taste. He was trying to deflect "congratulations" for his analysis of the threat.

Tomorrow, Trump has promised to give his full - no doubt incendiary - response to the Orlando attack in the form of a "major" speech.

We know where this is going. The debate on national security, counter-terrorism and gun laws will all be poisoned by the politics of the presidential race.

Trump will seize even more air time on the US networks and dominate all social media. Within hours of the attack, he demanded President Obama step down for his refusal to use the words "radical Islam." (The White House judges that such a phrase will only undermine moderate Muslims whose support is so crucial in the war on the Islamic State).

So even before the crime scene has been cleared, and while the many wounded are still being treated in Florida hospitals, this tragedy is being exploited by Donald Trump. Just as everyone feared it would be.

The question is whether Americans buy his narrative that he has the "solution." Or will they judge that leadership requires empathy and thoughtfulness?