problems with glMatrixMode

My program normally runs in model matrix mode, but I have one object that I want to draw using projection matrix mode. However, for some reason, after the first time I call glMatrixMode(GL_PROJECTION); none of my other stuff draws, even if I try to set the matrix mode back to model view. Any ideas what the problem might be?

If it makes any difference, I am also using depth testing for the rest of my program, but disabling it at the same time as I call glMatrixMode(GL_PROJECTION), and re-enabling it at the end of the function.

Nevermind, I figured it out. I was just pushing my matrix into the wrong stack.