Would someone please clarify for me John McCain’s position on when the U.S. should withdraw troops from Iraq?

McCain, the Republican presidential candidate, has said he opposes the plan by Democratic candidate Barack Obama to bring all U.S. forces home within 16 months of Inauguration Day.

Any withdrawal of troops from Iraq "must be based on conditions on the ground," McCain said on Monday.

“When you win wars, troops come home,” he said during the same remarks. “He (Obama) has been completely wrong on the issue.”

But then, later on Monday, McCain said: "We've succeeded (in Iraq). We're not succeeding, we've succeeded.”

Doesn’t “we've succeeded” mean we’ve won? And didn’t McCain, just a few hours earlier, say that “when you win wars, troops come home”?

Why, then, does John McCain oppose the withdrawal of U.S. troops from Iraq?