PRESIDENT BUSH is making a big mistake in announcing that he wants to send up to 6,000 National Guard troops to the southern border. What a shoddy way to say thank you to troops who have seen plenty of action in Iraq and after Hurricane Katrina. It is also an insult to conservative and moderate voters, whom he apparently thinks this feckless gesture will appease. The whole focus on the border shows that Bush is not serious about curbing illegal immigration. Washington already has increased the ranks of the Border Patrol, which is good. Meanwhile, as many as one third...