Have the president’s attacks worked? When the Obama campaign launched its Bain attack on May 15, the race was tied at 45% in Gallup’s tracking. As of Tuesday, Gallup had it virtually unchanged: Mr. Obama 47%, Mr. Romney 45%.

Still, they have had an effect. The Romney campaign’s response—which included whiny demands that the president apologize for his attacks—has unsettled GOP activists, causing them to wonder how prepared Mr. Romney and his team are for the mudfest they’ve entered. The attacks have drawn attention to the Obama campaign’s demands that Mr. Romney release more years of tax returns. And they’ve allowed Mr. Obama to avoid talking about the continually bad economic news—the lousy June jobs numbers, last Friday’s drop in consumer confidence, Tuesday’s drop in retail sales and more.

The danger for Mr. Romney is that if these charges go unrefuted, they could discourage swing voters from going for him this fall when they decide whom to support. Therefore, Mr. Romney should challenge Mr. Obama directly—as he did effectively on Tuesday and Wednesday—but in a way that makes the Republican bigger and more presidential than the incumbent.