If the latest Reuters/Zogby poll is to believed, the drawn-out Democratic primary battle has undoubtedly helped John McCain. In last month’s R/Z poll, Obama lead McCain by a 47-40 margin. This month? A complete turnaround.

McCain leads 46 percent to 40 percent in a hypothetical matchup against Obama in the November presidential election, according to the poll.

As for his performance against Clinton, McCain’s actually lost a few percentage points in his lead.

Matched up against Clinton, McCain leads 48 percent to 40 percent, narrower than his 50 to 38 percent advantage over her in February.

McCain still maintains a larger lead over her than over Obama, but the trend is important to watch.