Paris's Notre-Dame cathedral is the latest setting for an Islamist terrorist attack

'Police have shot a man who attacked an officer with a hammer outside the Notre-Dame cathedral in Paris.

The man shouted "This is for Syria" during the attack, officials say.

...

Tourists fled for cover as the attack unfolded. Hundreds of people were at the cathedral at the time.

France is in a state of emergency since attacks by jihadists in Paris killed 130 people in 2015.

French Interior Minister Gérard Collomb said that the assailant on Tuesday afternoon had carried the identity card of an Algerian student.'

More here http://www.bbc.co.uk/news/world-europe-40178183

What are we going to actually do about the growing menace of Islamist terrorism in Europe? Based on previous experience of European leaders, absolutely nothing.

What should we do?