Most everything Sen. Marco Rubio (R-FL) does these days is related to his self-appointed position as a top leader of the US push for regime change in Venezuela. His decision to Tweet a before and after picture of former dictator Moammar Gadhafi is being seen in that context.
Gadhafi was violently overthrown in 2011 in a US-backed push for regime change. He was ultimately caught by US-backed rebels and publicly killed. Rubio’s Tweet is seen as a “warning” to Venezuela’s President Maduro, who the US is in the process of trying to overthrow.
At best it would be a threat to see Maduro killed Gadhafi-style, or potentially an end-game goal for the Rubio-led push, with US-imposed regime change almost certain to include a violent death for a perceived enemy.
Though Rubio says he previously wanted the US “solution” to Venezuela to be non-military, he now believes that ousting Maduro is important enough that a “very strong argument” can be made to send the military in.