Turning Launchpad LED on and off with Button Switch S2

I am very new at learning to program the MSP430. Using Code Composer Studio v5, I am working on turning the Launchpad LEDs on and off with switch S2 with the MSP430G2553.

I borrowed the following program from the TI Wiki, but all that happens when I run the program after Debug is that the red LED illuminates and remains lit even when I push S2.

Can anyone tell me what am I doing wrong? Why does the red LED even illuminate when the "if" routine is supposed to tell it to do so only when S2 is pushed? Is the P1DIR |= 0x01 expression actually causing the LED to illuminate

You can see that I have some very basic questions.

The program can be found at  http://processors.wiki.ti.com/index.php/MSP430_LaunchPad_Interrupt_vs_Polling

Thanks in advance,

Earle

#include <msp430g2553.h>

void main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
P1DIR |= 0x01; // Set P1.0 to output direction

while (1) // Infinite Loop
{
if ((BIT3 & P1IN)) // active low switch
{
P1OUT &= ~0x01; // if P1.3 is 1(not pressed),reset P1.0
}else
{
P1OUT |= 0x01; // else set P1.0
}
}
}