Prime Minister Mariano Rajoy is widely expected to win a crunch parliamentary confidence vote.
Spain was close to turning the page on a 10-month political crisis Saturday as lawmakers readied to vote the conservatives back into power, although at the head of a government with unprecedented opposition.
Aided by divisions among his rivals, Prime Minister Mariano Rajoy is widely expected to win a crunch parliamentary confidence vote later Saturday which will see him officially reappointed as Spanish leader.
In a sign of how deep the divisions run, former Socialist chief Pedro Sanchez, a staunch opponent of Rajoy who was ousted in a party rebellion this month, announced he was quitting parliament just hours before the vote in a tearful media appearance.
Near parliament, hundreds of protesters unhappy about corruption and sweeping spending cuts during Rajoy's first term took to the streets under strong police watch, shouting "they don't represent us."
"I don't agree with what is going to happen today," said Carmen Lopez, a 65-year-old retired computer technician.
"It's going to be the same government, or similar, than the past four years, which was disastrous for Spain."
Party leaders this week appeared far from conciliatory as the confidence vote neared.
They came out fighting, criticising Rajoy and each other just as they did over the past 10 months as the country went through two inconclusive elections.
This unstable period saw Spain go from jubilation and hope after polls last December ended the two-party system as millions voted for two upstart parties to disillusion following repeat polls in June that yielded similarly inconclusive results.
Rajoy's Popular Party (PP) won both elections but without enough parliamentary seats to govern alone. As no political grouping was able to agree on a viable coalition, Spain looked set for an unprecedented third election in less than a year.
This all changed last weekend when the Socialists swallowed a bitter pill and opted to abstain in Saturday's confidence vote to avoid more polls, after weeks of bitter in-fighting that saw Sanchez ousted as leader.
This gives Rajoy, the official prime ministerial candidate, enough traction to see him through the vote.
In retaliation, Sanchez announced Saturday he had resigned as lawmaker, unable to choose between going against his principles and abstaining, or going against his party and voting no to Rajoy.
In an announcement just hours before the vote, the 44-year-old emphasised "how painful the decision was" before breaking down and choking back tears.
Unlike when he came to power in 2011 with an absolute majority, Rajoy's party will only have 137 out of 350 seats in parliament and will face huge opposition, forcing him to negotiate every bill.
First on his list will be a 2017 budget, which may need at least five billion euros ($5.5 billion) in spending cuts to reduce the deficit under EU pressure.
But this is likely to face stiff opposition both in parliament and on the street, and already Rajoy's rivals have pledged to vote against it.
Rajoy, meanwhile, has called on the opposition to let him govern effectively, pointing to the return to growth and drop in unemployment on his watch after a devastating economic crisis.
Political analyst Pablo Simon said there was "no doubt" his term in office would be the most "turbulent" ever in Spain and could prompt Rajoy to call early elections if he keeps hitting brick walls.
But he predicted Rajoy would not find it as difficult as expected.
The Socialists, for one, will need time to rebuild in the opposition and will not want early elections, knowing they would fare badly after their very public breakdown.
The PP also has a majority in the Senate, and may be able to form pacts with smaller parties in the lower house to see laws through, Simon added.