Unfortunately there is some spurious locale dependency.
For example, this code give different results depending on locale (but time settings does not matter):
a1 = "11/9/2012 8:58:19 AM";
a2 = "11/9/2012 8:58:19";
a3 = "11-9-2012 8:58:19 AM";
a4 = "11-9-2012 8:58:19";
Show( Parse Date( a1 ), Parse Date( a2 ), Parse Date( a3 ), Parse Date( a4 ) );
//JMP 10.0.1 in OS X 10.8.2 region set to "Sweden", 24 hour time
Parse Date(a1) = .;
Parse Date(a2) = 09Nov2012:08:58:19;
Parse Date(a3) = .;
Parse Date(a4) = 09Nov2012:08:58:19;
//Same computer, but region set to "USA", 24 hour time
Parse Date(a1) = 09Nov2012:08:58:19;
Parse Date(a2) = 09Nov2012:08:58:19;
Parse Date(a3) = 09Nov2012:08:58:19;
Parse Date(a4) = 09Nov2012:08:58:19;
//Same computer, region set to "UK", 12 hour time
Parse Date(a1) = .;
Parse Date(a2) = 09Nov2012:08:58:19;
Parse Date(a3) = .;
Parse Date(a4) = 09Nov2012:08:58:19;
//Same computer, region set to "UK", 24 hour time
Parse Date(a1) = .;
Parse Date(a2) = 09Nov2012:08:58:19;
Parse Date(a3) = .;
Parse Date(a4) = 09Nov2012:08:58:19;