US President Donald Trump loves signing ceremonies, like with his executive order last week to potentially penalize social media platforms such as Twitter.Despite the order being wrapped up in a heated US domestic partisan politics debate, could it have the side effect of combating jihad and antisemitic uses of social media? First, there is an asterisk to his executive order: Legally, it is probably close to meaningless.The reason is that the US Congress already has a decades-old law on the books which gives social media companies exemptions from being sued in relation to the content posted by their users.The idea is that they are merely conduits and cannot be held accountable for what their users post. They say this is true both legally, since they are not the ones posting, and practically, because they cannot effectively police abuse of their platforms by billions of users worldwide.This exemption has been challenged by numerous groups regarding the use of social media for pornography, antisemitism and even by jihadists (in recent lawsuits by the NGO Shurat Hadin.)Each time, the courts have expressed sympathy with the plaintiffs, but noted that the Congressional exemption leaves them powerless to intervene.Presidential orders cannot contradict laws passed by Congress – for a law to be passed by Congress it also means a prior president signed it – so his order is symbolic at best. If it reaches the US Supreme Court, it will probably be cancelled.But this may not be the end of the story.Before that point, a lower court might try to use Trump’s executive order to interpret an exception to the Congressional law and try to penalize a social media platform.And Trump’s order may create momentum for Congress to revisit the issue.But any change to the law would require a bipartisan approach, since control of Congress is currently split between Democrats and Republicans, and Democrats will not want to be seen defending Trump’s Twitter attacks.More likely, the main impact will be that Twitter, Facebook, YouTube and others will start to more aggressively self-police their content when it comes to being used by jihadists or antisemites.This progression has already happened in Israel.Former justice minister Ayelet Shaked was set to push through a law with a range of potential penalties against Facebook and other social media giants, until the platforms cut quiet side deals to self-police.This self-policing does not mean that Facebook can prevent a terrorist or antisemite from ever protesting problematic content. However, it does mean that new cyber units in the Shin Bet (Israel Security Service), police and Justice Ministry can quickly flag problematic posts for Facebook, and that in such cases, around 95% of them are removed voluntarily.It also means that, as they start combating these phenomena on their own, Facebook and others have invested a large amount of money in finding jihadist accounts or fake accounts used by countries like Iran to spread fake news.But many would say that efforts of these platforms in the US lag behind their efforts in Israel or in Europe, where the EU has officially regulated the issue.Many of the same problems with Russia trying to use social media platforms to create chaos in the US and influence American elections, as they did in the 2016 presidential election, are still a challenge today.Traditionally, the explanation for this disparity is that the right to free speech in the US is relatively stronger than it is in other democracies. Facebook and Twitter frequently plead that they do not want to walk down the slippery slope of deciding what kinds of speech are too extreme. But voluntary enforcement is exactly what leaves these platforms vulnerable to Russia, jihadists and antisemites.The bottom line is that it will prove difficult to leverage the Trump executive order – which comes out of his personal fight with Twitter over his attack on mail-in voting – to roll back jihadist and antisemitic use of social media.But if the social media giants are moved by societal pressure to voluntarily do even some catching up with Israel and the EU in combating these phenomena, the situation might become better than it is today.