at or on the leading edge

[ostap77]

"The US forces will be on the leading edge of the allies forces."

Is it on or at the edge?

[billmcd]

"The US forces will be on the leading edge of the allies forces."

Is it on or at the edge?

I think you will most often hear "at".

[ostap77]

I think you will most often hear "at".

I hear from a spokesman for the White House that the US forces are on the edge.......?