Asked why attacks are increasing, Fantini said: "This is a complicated question to answer because so often we don't know the identity -- or even the ideological motivations -- of the perpetrators. Sometimes the motives are clear, but other times we have to make our best guess. As radicalized movements increase in both numbers and intensity, the number of attacks on churches seems to rise."
She continued: "I have said before that churches are 'lightning rods' for activists. And each group has their own reasons for choosing to attack a church. Churches can represent 'the patriarchy,' 'authority,' 'tradition,' 'homophobia,' 'the Christian West,' etc. Islamists target churches for different reasons than anarchists, for example. But all of these groups are more and more active these days."
"A further complicating problem is the unique nature of churches which tends to make them more vulnerable -- they're open to the public during the day and they usually don't have much, if any, security."
For Fantini, the most effective way to respond to the attacks is through local action.
She said: "I think it starts with church communities and the faithful. They have to demand protection and speak out when their churches are targeted. In France, there is an excellent initiative started last year called Protège ton église (Protect your church). Young Catholics organize themselves in towns across France to check on their churches at night, peacefully dissuade or report vandals, and generally make their presence known."
"Governments also need to start protecting vulnerable churches with as much attention as they do other vulnerable places of worship."
Gregg noted that French bishops have spoken out about the attacks, including Archbishop Michel Aupetit of Paris and Archbishop Éric de Moulins-Beaufort, president of the French bishops' conference.
"It has also been a subject that French bishops have raised in regularly scheduled meetings with the state authorities, including as recently as March this year when they asked for a security plan for churches to be put in place," he said.
"So some French bishops have been proactive on this subject. Nonetheless, the attacks continue. Part of the challenge is that these are, for the most part, open buildings so that Catholics and others can enter and pray; they are not supposed to be, and should not be, mere museum pieces."
Gregg suggested that bishops elsewhere in Europe should follow the French bishops' lead.
"By that I don't mean yet another anodyne NGO-like statement of the type that too many European bishops and bishops' conference bureaucracies are prone to issue, and which no one reads," he said. "I mean bishops and clergy speaking about the topic to the faithful and talking about it more frequently in the public square."
"They could be asking questions such as 'Why are so many Europeans rather blasé about attacks on buildings and sites that are part of Europe's cultural landscape?' Or 'What does ongoing vandalism to religious sites say about how European attitudes towards religious tolerance?'"
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"In other words, it is an opportunity to spark wider discussions about topics ranging from religion's place in modern Europe to Christianity's irreplaceable contribution to the development of Western civilization."
Fr. Benedict Kiely, the founder of Nasarean.org, a charity supporting persecuted Christians, told CNA that Christians should not watch silently as churches are attacked.
"Practically, cathedrals, etc, must receive proper protection from civil authorities and any attacks on churches or religious images must be treated as what they are -- hate crimes," he commented.
"Secondly, we must loudly raise our voices to decry these continuing attacks and not be cowed into silence. Our leaders must be courageous."
Reflecting on the future, Fantini said: "How much worse can it get depends on what line activists are willing to draw for themselves. Will they stop at burning an empty church? Will they stop at decapitating statues? Certainly the climate today, both in Europe and America, does not leave me optimistic that things will improve soon."