The issue of foreign influence cropped up several times in yesterday's Parliament sitting.

Law and Home Affairs Minister K. Shanmugam spoke about it in response to questions from two MPs, who wanted to know what more could be done to punish the purveyors of fake news on the Web.

It also featured during the debate on the Public Order (Amendment) Bill, when Mr Shanmugam went through the reasons for tightening security at large-scale events and preventing foreigners from using them to promote political causes.

To be sure, the Government has always been watchful against outside interference, and it is a longstanding principle that foreign entities are not allowed to engage in domestic politics here.

But the issue has taken on greater urgency in a world where borders have become increasingly porous and foreign influences are harder to recognise or define.

Take fake news. Mr Zaqy Mohamad (Chua Chu Kang GRC) had asked about the likelihood of such news being manipulated by foreign parties to influence society, including election outcomes and social cohesion.

During the debate yesterday, Mr Shanmugam gave examples of how this had already been attempted elsewhere.

Foreign-controlled websites were said to have published skewed articles in a bid to influence a crucial referendum in Italy in December, on a package of constitutional reforms put forward by then-Prime Minister Matteo Renzi, who resigned after the referendum defeat.

After the United States presidential election, it also emerged that fake news stories that could have influenced the election results were created by teenagers from a small town in Macedonia driven by the profit motive.

What is interesting, though, is that these incidents of possible foreign influence were all discovered after the fact.

The battle against fake news, thus, is not simply about correcting "trivial factual inaccuracies", but falsehoods that could cause real harm and are the result of state actors.

Mr Shanmugam noted: "There is a much more serious dimension to all of this because fake news today, we must assume, can be used as an offensive weapon by foreign agencies and foreign countries.

"We have already seen examples of that - to get into your public's mind, to destabilise your public, to psychologically weaken them, and impact your agencies. That is a very serious threat, and it will be naive for us to believe that governments or state agencies do not engage in this. There is enough evidence that they do," he added.

On fake news, the need to be on guard against foreign attempts to influence domestic politics and harm society is clear, and most Singaporeans would not disagree.

But this may not be so in the case of public events, as the debate suggests.

Speaking on the Public Order (Amendment) Bill, Nominated MP Kok Heng Leun argued the change to the law - to require event organisers to put in place stringent security measures the police deem necessary - could make it hard for civil society groups to invite foreign experts to speak at events.

He asked for clearer definitions from the minister on what would constitute foreign influence.

To this, Mr Shanmugam said "absolute clarity" was not possible, and events will have to be assessed on a case-by-case basis.

To illustrate, he cited an example of how even an event on animal welfare could be hijacked by foreigners to influence politics in Singapore.

"Supposing, under the rubric of animal welfare, Indians from India want to finance an animal welfare event in Singapore protesting against the selling of beef in Singapore and they want to involve Singapore Hindus... Do you think we should allow (this)?"

Most will agree on this point, but the lines are not always so clear.

Last year, when the Ministry of Home Affairs sent out a reminder that foreign entities would have to apply for a permit to take part in Speakers' Corner events, such as the Pink Dot rally, there had been disquiet among some segments.

Companies like Google and Facebook had been sponsoring the annual lesbian, gay, bisexual and transgender (LGBT) community event for years without issue, but would no longer be able to do so without a permit, and some saw this as censorship. Organisers also worried about funding.

As it turned out, their worries were unfounded, a point Mr Shanmugam noted. At least 50 local companies have pledged to sponsor this year's rally.

Singaporeans have shown that they will step up to the plate on domestic issues they feel strongly about, and in which they want to have a say. On these matters, they need no outside influence to help chart their destiny.