She has proven herself a superb speaker on behalf of her pet projects and is now a veteran campaigner for her husband. She’s also remained highly popular — even as the president’s ratings have plummeted.

She could represent the Democrats’ best chance to pick up a desperately needed — and winnable — seat. A December 2012 Public Policy Polling survey put her ahead of Kirk, 51 percent to 40 percent. Democratic leaders’ pressure on her to run might get intense.

But the most acute pressure could come from within. Anyone who has listened to her speeches, particularly on the campaign trail, understands that she is a dedicated liberal, who believes unreservedly in the power of government to transform lives.

Obama views the battle between Republicans and Democrats as a struggle for the soul of the nation.

“Who are we?” she repeatedly asked while campaigning in 2012. She said the election result would affect the country “for decades.”