basemapLayer = arcpy.mapping.Layer(path_to_your_basemap_lyr_file)
mxd = arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListDataFrames(mxd, "*")[0]
arcpy.mapping.AddLayer(df, basemapLayer, "BOTTOM")Hi Matt,
Thank you for put this process in a script form, it is very useful!
Best regards,
Pedro Bravini