Exactly 40  years ago today, India found itself in the grip of the Emergency. It brought with it a crackdown on civil liberties and media freedom, the illegal detention of members of opposition parties and political activists, the introduction of authoritarian and arbitrary laws, and a programme of  forced sterilization. Not surprisingly, the Congress has remained silent about that period. After all, it was Indira Gandhi who imposed the brutal 21-month decree. Instead, it’s been the time for the party's opponents – heartland socialists, Lohiaites, Dravida parties and labour unions – to recount the horrors of those times. But most of all, it is the leaders of the Bharatiya Janata Party (or the Jan Sangh, as it was then known)  who tell the most fervent tales about the Emergency.

Just over a week ago, the octogenarian LK Advani, an erstwhile Jan Sangh warhorse and one of the founders of the BJP, recalled the days of the Emergency in a long interview to the Indian Express.  He even warned that “the forces that can crush democracy… are  stronger" today. Though some saw it as a barb against the younger man who usurped his pole position in the party, Advani has been making statements like this long before Narendra Modi appeared on the scene. Over the years, BJP leaders have frequently evoked the Emergency to counter attacks on their leadership or to taunt the Congress But what is it that keeps them in such political thrall to that period during which the Constitution was suspended?

Here’s are the main reasons.

1. Historical identity: It was the Emergency that gave birth to the BJP, so it’s only natural that it looks at the period through the lens of childhood nostalgia. The party still remembers the exhilarating years of revolutionary euphoria, when the erstwhile Jan Sangh joined the Janata Party to overthrow Indira Gandhi in the 1977 elections. That was the first time India did not have a Congress government. LK Advani became the first non-Congress Information and Broadcasting minister, while Atal Behari Vajpayee got the External Affairs portfolio. Their government not only held enquiry commissions on the excesses of the Emergency, but even briefly arrested both Indira Gandhi and her son, Sanjay, who were seen as invincible and terrifyingly ruthless. It was a heady period.

2. No Freedom Movement contributions: The participation of the Rashtriya Swayamsevak Sangh –  the hardline Hindutva parent of the Jan Sangh and the BJP – in the Independence movement is pretty hazy. Historians have shown how the RSS was more focused on organising and militarising Hindus first, which meant that its cadres were barely visible in the various anti-British movements. Nor did they participate in the broad coalition of  freedom fighters who either were under the Congress umbrella or tied to the Communist movement or revolutionaries like Bhagat Singh and Chandrashekhar Azad. Perhaps the RSS had its own ideas about what freedom should achieve – primarily a Hindu nation. With its notable absence in the freedom struggle, the Sangh’s first real jump to the battlefront was during the Emergency. That's why leaders like Advani and Vajpayee have waxed so eloquently about their revolutionary Emergency days.

3. Advani's first incarceration: It was during the Emergency that Advani had his first jail term as a political radical,  when he spent 19 months inside a Karnataka jail. “I have not seen British rule but from what I know, from books… I can say that in so far as the ruthless assault on our liberties is concerned, there was nothing comparable in those days to the Emergency,” he told the Indian Express last week. It was also here, as Advani reveals in his autobiography, My Country, My Life, that he discovered new meaning to life – the “boon of solitude” the joys of reading, learning Kannada, enjoying badminton and table tennis.

In prison, Advani channeled his rebelliousness into writing a booklet titled  A Tale of Two Emergencies. Among his sources of inspiration was William Shirer’s The Rise and Fall of the Third Reich.  He said that the booklet was his contribution "to the underground literature for use by pro-democracy activists through the Lok Sangharsh Samiti formed by JP", as the opposition leader Jayaprakash Narayan was known.  In the booklet, Advani compared what Hitler had done in Germany to what the Congress government was doing during the Emergency. He wrote five more pamphlets while in jail, which were later collected in a book called A Prisoner’s Scrapbook. It was a political christening Advani cannot forget.

4. Vajpayee's 1942 nightmare: Vajpayee’s role in the Quit India movement has been noted in every celebratory article about the former prime minister. But as a Frontline magazine investigation noted, Vajpayee and his brother, who were briefly jailed for participating in a local agitation, were let off when they pleaded that they were only following the crowd, had caused no damage, and did not the share their objectives. Worse, Vajpayee named a fellow freedom fighter as the person who led the mob. In fact, Vajpayee confirmed to Frontline that the signature on the confessional statement was indeed his, though in his last year as prime minister, Vajpayee said the reports were malicious and defamatory. So, it is the Emergency that really made Vajpayee the statesman that he wanted to be. (More on the 1942 fiasco here.)

5. Guilt complex: Advani’s interview to the Express succinctly explained how the BJP’s found place in history during the Emergency.  “The Partition was British guilt," he said. "The Emergency is ours.”