Today, Juan Guaidó, the president of the National Assembly of Venezuela, assumed the role of acting President of Venezuela, invoking specific articles of the Venezuelan Constitution as the basis for doing so.
The government of heretofore President Nicolás Maduro is illegitimate:
-- in 2015, his allies in the legislature stuffed the highest court with Maduro-allied judges
-- in early 2016, the highest court removed several opposition politicians from the legislature, thus weakening its power in opposition to Maduro
-- in 2017, the highest court granted more executive powers to Maduro
-- also in 2017, Maduro gathered allied politicians in a constituent assembly to draft a new constitution, which would keep him as president indefinitely
-- and in August 2017, that constituent assembly declared itself the true legislature, even though the actual legislature continued to exist
-- in 2018 presidential elections, multiple opposition parties were banned from participating, basically setting it up for Maduro to win automatically
Maduro is a modern-day Manuel Noriega (the former leader of Panama in the 1980s), in the sense that he has quickly consolidated power (see above) and thus effectively become a dictator; and he has used that strong centralized power to run a narco-trafficking business essentially unopposed by any internal domestic elements, thus amassing financial wealth, which in turn is used to pay off and placate the armed forces to allow the drug operations to continue, despite the ever-worsening misery and hunger of the general population around them.
It is a textbook case of what is called a kleptocracy, which is literally a 'government of thieves.'
At this time, international pressure is building on behalf of Guaidó and even more strongly than before against Maduro. Meanwhile, the lives and livelihood of the people of Venezuela hang in the balance. Please pray that a transition does indeed take place and that, God willing, it may be peaceful and bloodless.
As a final footnote, I'll note that I wouldn't doubt that Trump would love to take the steps that Maduro -- a stereotypical Third World dictator -- took to purge his opponents from all branches of government and consolidate all power under himself. It's quite ironic, then, for Trump to foment Maduro's downfall.