the border is not that bad
The border with Venezuela is mostly a big savanna, and we have a couple tanks there
The big problem is getting enough soldiers, tanks and other stuff over there. Only time we had a military operation in another country in our northern borders was Operation Traíra against FARC, not an invasion against a proper military.
There are only around 12 million people in our northern states, they're mostly empty jungle with a couple cities, and our armed forces are mostly in the southeast and near the Atlantic, a big problem that has been known for centuries but never adressed, partly because there have been no threats over there, we only had to deal with military action in the northeast's coast and in the Argentina/Uruguay/Paraguay border near the La Plata river.
We also have one paved road to Venezuela, so that could be used, but getting enough people over there would be hard. We have an advantage when it comes to everything, especially the navy, but our navy is all in Rio and it would take time to get them there.
Colombia would have an easier time to organize an invasion, and their logistics would be easier, but their armed forces are not made to fight other countries anymore, they're entirely focused on counter-insurgency.
I think they don't even have tanks anymore, and they focus on small well-trained groups to go full commando or shoot people from helicopters and shit, which is smart given their geography and actual military challenges. but bad for wars
I proposed this scenario to admiral binkov several times, but I never made it to his polls :( (both venezuela x colombia and venezuela x brazil)
binkov.com/
this, and Colombia would be even less legitimate since they hate each other and have had beef among them for several years, even before the commies got to power and they still have contested land between them. Plus president Santos is a complete fucking cuck who sucks guerrilla dick.