One of the most common accusations to be levelled at MPs is that they are “out of touch”. It is sometimes true, but not as often as people may think. The charge is frequently a device to portray ideological difference as cultural alienation. We disagree with a politician’s opinions, and want that to indicate some moral detachment from the ordinary people they are elected to represent. In reality, most MPs are more closely connected, more palpably in touch with the electorate than their many critics appreciate. David Amess was making contact with his constituents – physically present, personally attentive, intimately available – when he was killed in his Essex constituency on Friday afternoon. Whatever the identity and motives of the killer – facts that will emerge in due course – the act is felt as an assault on democracy, as well as a cruel human tragedy. The MPs’ constituency surgery is one of the least examined institutions of British politics partly because so much of what happens there is confidential. Anyone who has had the privilege of sitting in on a session will know how intensely private and often harrowing the stories can be of vulnerable people, anxious, adrift in chaotic lives or hostages to dysfunctional bureaucracy, turning to their elected representative for advice – or sanctuary. There are often time-wasters, too, cranks and vexatious complainants. But variety and unpredictability is a function of the open door. A wide spectrum of characters, opinions and temperaments are found in every constituency, and each is entitled to be heard. But the MP is entitled to hear them without fear of violence. Democracy shrinks when every new figure in the doorway might cast a murderous shadow. In 2010, Stephen Timms, Labour MP for East Ham, survived a knife attack in his constituency office. Once recovered from life-threatening injuries, he went straight back to holding face-to-face constituency surgeries, considering it an essential fulfilment of the duty to which he was elected. In June 2016, Jo Cox was shot and stabbed outside the library she was due to visit in her West Yorkshire constituency. She had been an MP for less than a year, which was long enough to make one of the most memorable interventions in the House of Commons for a generation. It was her maiden speech, celebrating the social and cultural diversity of the area she represented. The peroration became her epitaph: “What surprises me, time and time again, as I travel around the constituency is that we are far more united and have far more in common than that which divides us.” It is a radiant truth too often submerged in the brackish foam of partisan rage. The shine on Cox’s words needs regular protection from the tarnish of corrosive cynicism. That which divides us has a nasty habit of shouting over the top of what we have in common. MPs from all factions in all parties will be united in shock and grief at the death of David Amess. They will also feel the cold shiver of vulnerability, since many of them will have received abuse and threats online and in person. And it is not just the MPs who are affected. Their families and staff are targeted. Many will have installed extra security precautions, not just in their constituency offices but in their homes, on the advice of police, when the threats are deemed to be not idle. Most will have been accosted at some point in the street, in the supermarket, at a local fete, and been told of their worthlessness, of their greed and corruption, of their complicity in all manner of foul policies and far-fetched conspiracies. MPs will have borne those verbal assaults with dignity and patience because it is part of the job. Or, rather, it has become part of the job and no one has yet worked out a way to restore boundaries of basic civility. If it is a choice between security and accessibility, British politicians have collectively stuck with the latter, which is the courageous path, but it is not a dilemma that they should face in a civilised democracy. For all the ferocity of a hyper-partisan political culture and the febrile, intemperate mood that seems to have become the permanent condition of Westminster, an immutable quality of parliament is its purpose as a house of representation. It may seem culturally remote, even out-of-touch. But an MP was killed today, in the act of getting in touch. David Amess was making the human connection between the institutions of democracy and the people who are represented there. On a day like this, we forget them-and-us. We are reminded: they are us. Rafael Behr is a Guardian columnist