Currently on display at the Reina Sofia Art Centre Museum in Madrid, the iconic Cubist painting - inspired by the Nazi bombing of the town of Guernica on April 26, 1937, which killed some 1,600 people - has become a universal symbol of the horrors of war.
But for the Basques, Guernica has an even stronger resonance because the town that gave its name to the painting is seen as the cradle of their identity.
This is where, under a fabled oak tree, Spanish kings for centuries vowed to respect Basque "privileges".
To this day, leaders of the semi-autonomous Basque regional government continue to make the following pledge: "Humble before God, standing on Basque soil, in memory of the ancestors, under the Guernica tree, in front of you, representatives of the people, I swear loyally to fulfil my duty."
Moving the artwork temporarily or permanently to the Basque country would help "end the democratic transition and begin the pacification and normalisation process" aided by the Basque separatist group ETA's ceasefire, Eusko Alkartasuna (EA), a ruling party in the regional government, said.
On April 11, the Basque government formally requested that Spain "temporarily" transfer the painting to the Guggenheim Museum in Bilbao for the 70th anniversary of the Guernica bombing.
Guernica on display at the Reina
Sofia Art Museum in Madrid
But the artwork by Spanish artist Pablo Picasso, who spent most of his life in exile, has suffered from its many travels around the world.
Commissioned by the Spanish republican government for the 1937 Paris World Fair, Guernica was displayed in various countries to collect funds for the republicans, who were squashed by the putschists of General Franco during the 1936-1939 Spanish Civil War.
For the director of the Reina Sofia Museum, Ana Martinez de Aguilar, moving Guernica to Bilbao is unthinkable.
"The art piece is in a very fragile state of conservation" and will not move from its current home, she told AFP.
While at the New York Museum of Modern Art (MoMA) in the late 1950s, the painting, measuring 3.5 by 7.7 metres, was covered with a layer of wax to correct cracks, tears and damaged corners.
Basque group ETA has only just
ended its campaign of bombings
As a result, it cannot be rolled or handled without creating a "wave effect" that could cause irreparable damage, according to experts consulted by the Reina Sofia in 1997.
Picasso's wish was that Guernica remain at MoMA or return to Spain once the country enjoyed "public liberties and democratic institutions".
The Prado Museum in Madrid and the Reina Sofia are currently celebrating the 25th anniversary of the painting's arrival in Spain in 1981, six years after the death of Franco, which marked a return to democracy.
Exhibited at first at the Cason del Buen Retiro, Guernica was transferred to the Reina Sofia in 1992.
Some experts say the painting could be moved one more time with its frame and placed in a container with all the necessary protection measures regarding humidity, temperature and vibrations.
But to no avail. Spain's culture minister Carmen Calvo has refused to order a new technical report, saying she does not wish to link Guernica with "the disappearance of terrorism".
"I do not do politics with pieces of [Spanish] heritage," Calvo said.
For Basque nationalists who laid claim to Guernica as soon as it arrived in Spain, the issue is especially frustrating.
"We have the bodies, they [have] the painting," EA's ruling coalition partner the PNV party said.