The thing is there never is really any need these days for Proof. As long as people feel this is happening then politicians will take advantage of those perception or create those perceptions. This is the reason why we are in this thread today because of feelings. I feel this is happening or I heard from someone, Youtube, tweet, political rally or statement.
When you really think about it you see how the current Republicans absolutely love this caravan of people coming to the US. Nothing plays better for them then to make statements it's the Dems funding them. Yep, the Dems is funding a caravan of people to illegal come into the US and somehow find a way to vote during elections. It definitely plays to the fears of their base very well even if there isn't a shred of proof to it. If that scenario doesn't work then they will proclaim they are trying to get here birth some babies and then those kids can vote Democrat in 18 years.
Since the popular vote doesn't matter, you really have to think about how this really plays out.
The debate isn't really whether or not its happening. Most agree its happening, but argue just not at a significant level.
Oh, I agree the republicans are benefitting from the caravan. It also puts the democrats in a weird position because they seem to be approving of it or ignoring it because they know independent voters generally are not happy about it. I'm not arguing the people on the caravan will vote, but it supports the narrative illegal immigration into this country is a mess.
The popular vote simply doesn't matter when voting for a president. Because we have a system that gives all states a say, but it still gives large states the most power. People ignore in the electoral college the democrats essentially start with the support of states like California, New York and numerous other states which is a lot of points in the electoral college. While republicans actually have to appeal to the working class if they hope to win the electoral college. Obama ran as a moderate and dominated. Hillary ran as left wing hack and got crushed in the electoral college.
However in local elections via the popular vote people can still vote for mayors, governors, senators, house representatives and other appointments that shape sates and the country. People actually want illegals voting in local elections and dems have been vocal about that.