title: Spain's Socialist leader says would back government on Catalonia
text: MADRID (Reuters) - The leader of Spain s Socialists, the main opposition to Prime Minister Mariano Rajoy s conservative People s Party (PP), said on Monday the party would back government action if Catalonia makes a unilateral declaration of independence on Tuesday.  We ll support the response of the rule of law in the face of any attempt to break social harmony,  Pedro Sanchez said during a conference in Barcelona.  