That get-out-the-vote effort will be centered in Boston and the academic hub of Cambridge, the liberal base of the state, which needs to come out strongly for Coakley to prevail. Obama’s last-minute rally for Coakley in Boston was a recognition that the campaign needs to re-energize his 2008 coalition, particularly getting young, African-American and Hispanic voters to the polls.

In Boston, her biggest ally is longtime Mayor Thomas Menino, whose urban political machine is legendary and helped him comfortably win reelection last year, despite opposing Democratic challengers running on a Brown-like message of change.

But last month’s Democratic primary results suggest she can’t automatically assume enthusiastic support: Even though Coakley won most municipalities across the state, Rep. Michael Capuano outpolled her in Boston and Cambridge.