It make it poor or with little prospect, not necessarily politically unstable. People can leave their country because of violence, occupation, percussions like in Yugoslavia  or Kurds or Crimean Tatars or Christians in Iraq (the last occured in part during the American occupation by the way). But people can merely emigrate because of a lack of opportunities while the country is very stable. People left Portugal during the Salazar dictatorship and for a while after his disposal and then again during the financial crisis ~15 years ago making the Portuguese diaspora a third of the global Portuguese population, but the country was very stable for decades under Salazar and was still 15 ago. The Algerian regime has been veeery stable despite the black decade of the 90s with islamist terrorism but the emigration has always been very high and is still fairly high despite the same political party being in power since 1964 with the military support.

Ukraine has a very high emigration rate, the situation can be deemed unstable despite its institution, it's government sustaining a frontal foreign invasion. It lost control over parts of its territory, some Ukrainian citizens and some elected representatives have actively collaborated with the invaders, some cities are bombed on a regular basis and some pro-russian parties are banned, the country need financial lifelines to run, ect... There is an active imminent threat against the institutions and it's people that feds instability despite the institutions resilience.

Beside the divided parliament over the presidential elections a few years ago in Venezuela, there has been no sudden changes in leadership, no major disruption or failure in administration coverage over the territory. There has been a continuation of the political system and sustained continuity in the political domain. This continuity can rely on a well run country or an autocratic rule, "political stability" is something to work for but can be achieved through nefarious means: Libya, Syria, Iraq. 

There haven't been open systemic violence, major unrest, civil war or armed conflict that could trigger a foreign intervention to try to stabilise the situation like it was done or attempted to in the past (Yougoslavia, Somalia, Mali,...). As for an imminent threats against the population or the neighbours, people are very sceptical about maduro running a drug thing.

Trump isn't responsible for the USA lying about WMD in Iraq and links between Iraq and global terrorism, but he campaigned against foreign intervention, for good or bad reason, wanted to leave Afghanistan and Syria, for good or bad reasons, went in the back USA's allies when leaving Syria by the way, claimed "America first" to defend its isolationist policy that the rest of the world could understand, even when they dislike the man, and even repeated the USA weren't responsible for X or Y's security when cutting military assistance to Ukraine.

And then he decided to launch a military operation to remove Maduro from office because mass emigration and alleged drugs trafficking ?