Adding Trump to Mt. Rushmore Impossible, Ex-National Park Service Head Says

MAGA supporters eager to see Donald Trump added to Mount Rushmore are about to be disappointed ... because it's nearly impossible to make an addition without destroying the landmark, TMZ has learned.

We caught up with former National Park Service Superintendent Dan Wenk on "TMZ Live" Tuesday, where he explained why the two-time president is never going to make it up onto the storied rock in South Dakota.

As Dan put it ... the mountain has been examined in the past and investigations determined that trying to make changes to the mountain's structure would run the risk of destroying it.

He continued ... "It will endure for a long time if nothing's done to it. But messing with the rock, is really not something you would want to do."

DW also mentioned the mountain's explosive past ... reminding "TMZ Live" viewers that Mount Rushmore builders used dynamite to carve the famed faces -- causing a number of cracks to form.

Not to mention, Dan feels Mt. Rushmore is a renowned piece of art and changing it would be akin to altering Leonardo da Vinci's "Last Supper" mural.