Dan Balz points out:When Sen. Barack Obama left Washington last week, he was under pressure to defend what Republican critics called an arbitrary deadline for withdrawing U.S. combat forces from Iraq. By Monday, the White House and rival Sen. John McCain’s presidential campaign were at pains to explain why the Iraqi prime minister had seemingly all but endorsed Obama’s relatively rapid timeline for getting out.I’ve gotten a bit of a chuckle over all of this. Whether Maliki...