If voters give Catalonia's leader Artur Mas strong support on Sunday, he has pledged to hold a referendum on independence from financially troubled Spain.
Voters in Catalonia on Sunday are choosing lawmakers for this wealthy Spanish region's parliament amid a threat from the Catalan leader to hold an independence referendum that would test the country's unity.
The regional government, led by Artur Mas, called early elections as part of a power struggle with the central government run by Prime Minister Mariano Rajoy centered on the size of Catalonia's contribution to national coffers.
But what began as a quarrel over money has turned into a test over Spain's territorial integrity.
If voters give Mas strong support on Sunday, he has pledged to hold a referendum asking Catalans if they would prefer to split from Spain at a time of deep financial crisis.
"These are the most decisive and transcendental elections in the history of Catalonia," Mas said after voting in Barcelona. "There is much at stake for all 7 million of us Catalans."
Polls forecast a majority for parties supporting a referendum on independence, a plebiscite that Spain's central government has ridiculed and called "unconstitutional."
According to Rajoy, only central government has the constitutional right to call a referendum and then it would almost certainly have to include the whole of Spain.
Mild winter weather and blue skies helped long lines form at many polling stations early Sunday. By 1 p.m. (7 a.m. EST), the Catalan government calculated that voter turnout was higher than in the previous seven elections dating back to 1988.
Rajoy has said that talk of independence is a side issue to the country's real problem, which is to find a way to create employment and address its deficit.