Framed portraits of the Venezuelan leader Hugo Chávez were propped up at various stops of President Nicolás Maduro’s recent whirlwind trip abroad, as the man at the helm of the nation with the world’s largest oil reserves begged for bailouts.

Posters of his predecessor also abounded when Mr. Maduro, a former bus driver, arrived home to a carnival-like welcome, as he drove the lead coach of a convoy that snaked through crowds of supporters.

Last week, in a speech before lawmakers, Mr. Maduro, whose approval rating has slipped to 22 percent as the Venezuelan economy teeters on the brink of collapse, again invoked his mentor in predicting a landslide victory in upcoming parliamentary elections. “I have no doubt that Chávez’s nation will deliver a great victory in the memory of Hugo Chávez in elections that are being held this year,” he said.

Since he was voted into office in April 2013 by a minuscule margin after Mr. Chávez’s death, Mr. Maduro has leaned heavily on the legacy of his predecessor, a populist who governed poorly but had magnetic charisma and shrewd political instincts. Woefully lacking on both fronts, Mr. Maduro has become increasingly erratic and despotic in a quest for political survival that seems more daunting by the day. Healthy oil export revenue allowed Mr. Chávez to build a robust network of patronage and create generous welfare programs during his 14 years in power. Those are becoming increasingly paltry on Mr. Maduro’s watch.