ISTANBUL — Two galleries in this city’s old European quarter recently opened exhibitions that showcase the political violence that convulsed the country in the 1970s. The echoes for contemporary Turkey were unmistakable.

SITE Intelligence Group, via Agence France-Presse — Getty Images

Alisan Sanli, identified as the bomber in the embassy attack last week.

On one wall are rows of old newspapers that chronicled through blaring headlines and grainy photographs the bloody street fighting and chaotic demonstrations that culminated in a military coup in 1980.

“Socialist revolution can only be achieved in Turkey through armed victory,” is how one newspaper of the time described the aims of a radical left-wing group that promised to use “revolutionary terror” and “urban chaos” to realize Marxist rule.

That bloody past burst violently into the present with last week’s suicide bombing of the American Embassy in the Turkish capital, Ankara. Initially assumed by many to be the work of Islamic extremists, the attack was quickly traced by the authorities to a man who sneaked into the country by boat from a Greek island in the Aegean Sea and was linked to a homegrown left-wing extremist group whose roots lie in the tumult of the ’70s.

As such, the bombing — even though it struck an American target and was motivated in part by American policy in the Middle East — revealed more about modern Turkey, its violent past and potential for instability than it did about the United States’ campaign against terrorism.

“This was no Benghazi,” wrote Ross Wilson, a former American ambassador to Turkey, in an online column for the Atlantic Council, referring to last year’s attack by Islamic extremists on a diplomatic outpost in Libya that resulted in the death of the American ambassador and three others.

For Turkey, the attack was an unpleasant reminder that despite a decade of reforms under the current ruling party, which is rooted in political Islam and headed by Prime Minister Recep Tayyip Erdogan, Turkey has yet to fully emerge from its dark past. Coming at a time when Turkey, with its prosperous economy and political stability, is trying to present itself as a model for countries convulsed by the Arab Spring revolutions, the attack served for many Turks as a reminder of the work left to put their own house in order.

“I think what people have forgotten, because of what happened here in the last 10 years, was how violent Turkish politics used to be,” said Gerald Knaus, of the European Stability Initiative, a policy research organization based in Istanbul. “In the last 10 years Turkey tried to emerge from this period of political violence and confront the skeletons in its closet. But we’ve forgotten how many skeletons there were.”

The attack also underscored how Turkey’s rulers sometimes use those skeletons to justify a growing crackdown on dissent, particularly with a campaign against the news media that has Turkey as the world’s leading jailer of journalists — more even than China or Iran.

“If the activist who blew himself up today had possessed a press card, they would have called him a journalist,” Mr. Erdogan said in comments broadcast on Turkish television shortly after the bombing last week that were immediately condemned by the advocacy group Reporters Without Borders.

Before the attack, Turkish security forces rounded up nearly 100 people accused of ties to the outlawed Revolutionary People’s Liberation Front, the organization the perpetrator belonged to, among them journalists, lawyers, even members of a rock band. The arrests were condemned by human rights groups as another example of Turkey’s broad use of antiterrorism laws to crack down on domestic opponents, particularly journalists and human rights lawyers, with no links to violent activities.

“Turkey’s overbroad antiterrorism laws have been used against an ever-widening circle of people charged for nonviolent political activities and the legitimate exercise of freedom of expression, association and assembly,” Human Rights Watch wrote in a report condemning many of the arrests.

Efkan Bolac, a member of the Contemporary Lawyers Association, was detained in that roundup but was released for lack of evidence.

“A lawyer doesn’t become a rapist if he represents one, or a drug dealer if he represents one,” Mr. Bolac said. “They claim we are members of a terror group, but how is that possible when we spend our entire time at courthouses?”

This week the American ambassador to Turkey, Francis J. Ricciardone Jr., said the F.B.I. was investigating the attack and suggested that the Justice Department might prosecute the group that carried out the bombing.

Yet the attack seemed out of another time and carried a whiff of cold-war-era intrigue, when links between the C.I.A. and Turkey were central to efforts by the United States to counter Soviet influence in the region. It also upended the conventional narrative about modern terrorism. “You’d think 10 years after the war on terror things would be clearer rather than more obfuscated,” said Bruce Hoffman, a terrorism expert at Georgetown University.

In his column in The Hurriyet Daily News, Nihat Ali Ozcan, a security specialist at the Economic Policy Research Foundation in Ankara, likened the attack to a “cold-war-style proxy war” that he speculated was the work of Syria, given the historical links between the group and Syrian intelligence. His observation was reminiscent of the paranoia of a bygone era. At one of the art galleries here, newspapers chronicled the 1977 May Day celebration in Istanbul, when leftist groups gathered for a demonstration that turned bloody.

“This attack is a provocation that links all the way to the C.I.A.,” one headline shrieked.