What's an "Invasion"?

Let's look at "invasion" by the numbers, shall we?

In 2003, the US invaded Iraq with 177,194 troops.

In FY 2018, 521,000 people illegally crossed the US border.

That's about 300% of the number we sent into Iraq.

Invasions are executed to achieve a debilitating disruption or change in the governance and/or tranquility of another nation.  That doesn't mean that an invasion has to be military.  There are other means, especially invading with the intent of remaining until death.

And that's why Trump is right:  this IS an "invasion."