CHARLOTTE — In seeking reelection during a weak economy, President Obama faces the challenge of convincing Americans that he’s made progress and deserves more time to finish the job. But he chose an odd way to go about it.

“I won’t pretend the path I’m offering is quick or easy,” Obama said. “I never have.  You didn’t elect me to tell you what you wanted to hear.  You elected me to tell you the truth.  And the truth is, it will take more than a few years for us to solve challenges that have built up over decades.”

This was an odd construction. It makes sense to argue, in the context of asking voters for more patience, to talk about how the path was never going to be easy. But it’s a bit odd for a president who has already been in office for nearly four years to say — present tense –  “I won’t pretend the path I’m offering is quick or easy.” Same with the idea of saying — present tense — that “it will take more than a few years” to fix the nation’s problems.

It wasn’t some throwaway line. It was one of the key themes of the speech. “The path we offer may be harder, but it leads to a better place,” he also said.

He revived the line at the conclusion of the speech: “Yes, our path is harder – but it leads to a better place.  Yes our road is longer – but we travel it together.”

When the dust settles on the convention, these lines might end up giving Republicans a big opening. For millions of Americans out of work, they can argue, the last three and a half years have already been a hard path. Now Obama is promising them a long, hard, road ahead.