First Post-Presidential Debate Poll Results: Romney Gains 4 Points, Trails Obama 48% to 43%

The first post-debate poll is out, and, as expected, Republican challenger Mitt Romney has narrowed President Obama's lead.

History shows that first debates lead to a bump in the polls for the challenger, and little to no change for the incumbent, exactly what was seen in a poll from Reuters/Ipsos after Wednesday night's debate.

Obama now leads Romney 48 percent to 43 percent. Romney gained four points after his impressive performance in the debate, helped along by the president's lackluster defense of his first term.

Romney's increased support likely comes from previously undecided voters who were impressed with his presentation. In general, with an electorate as divided as this one, no one's mind is changed enough by a debate to completely switch sides.

Nothing that happened on Wednesday would convince an Obama supporter to throw their allegiance to Mitt Romney, and vice versa. Instead, candidates must fight for that narrow band of voters who are still deciding at this late stage in the campaign.

This usually requires a shift toward the middle of the political spectrum, which viewers saw on Wednesday, as a less conservative Mitt Romney lauded his own achievements as governor of liberal Massachusetts, an association he shied away from during the Republican primary debates.

In addition, the Ipsos poll shows Romney with a 51 percent "favorable" rating, up from 46 percent pre-debate, the first time more than half of voters have had that opinion of him. Obama still leads slightly on that metric, with 56 percent of voters having a favorable view of him, unchanged from before the debate.

But if history continues to repeat itself, Romney may still be in trouble. Since the first televised presidential debate in 1960, the candidate in the lead after the first debate ended up winning the presidency. While Romney has closed some of that gap this week, Obama is still up by five points, more than enough win reelection in November.

Whether Romney's rally continues remains to be seen.