* Previewing Obama’s deficit reduction speech: A White House official emails a preview, saying that the core of Obama’s vision will be “shared prosperity and shared responsibility”:

President’s proposal will build off of the deficit reduction measures included in his 2012 budget and will borrow from the recommendations of the bipartisan Fiscal Commission he created. The President will lay out four steps to achieve this balanced approach, including: keeping domestic spending low, finding additional savings in our defense budget, reducing excess health care spending while strengthening Medicare and Medicaid, and tax reform that reduces spending in our tax code. The President will make clear that while we all share the goal of reducing our deficit and putting our nation back on a fiscally responsible path, his vision is one where we can live within our means without putting burdens on the middle class and seniors or impeding our ability to invest in our future.

The declaration that Obama will “borrow” from the fiscal commission is a suggestion that it won’t be the primary model for his speech. He wants to be seen taking ideas from many sources to craft a vision that is uniquely his, which would be in keeping with what we know of his M.O. The mention of “shared responsibility” and the vow to strengthen Medicare and not to put “burdens” on seniors is encouraging, and suggests that Obama may try to draw a sharp contrast with a GOP vision whose values and priorities are out of whack.

But we still don’t know whether Obama will make a persuasive and compelling moral case for an expansive vision of Democratic governance, or whether he’ll draw any sharp lines, or whether he’ll lay down a baseline that’s non-negotiable. And of course, when it comes to “borrowing” from the fiscal commission and “strengthening” Medicare, the details are what will count.

* Newsflash: Majorities oppose cutting Medicare, favor tax hikes on the rich: The new USA Today Gallup poll helpfully supplies public opinion context: By two to one, Americans support only minor changes or none at all to Medicare; meanwhile, 59 percent support higher taxes on families making $250,000 or more.

Also: Americans narrowly oppose more significant spending cuts, 47-45. These numbers suggest that the public might be receptive if Dems make the debate about GOP priorities, as spelled out yesterday by Paul Begala.

* Obama set to draw sharp lines? Marc Ambinder reports that the President will lay down a variety of things he cannot accept, such changing Medicare as we know it, or a budget approach that doesn’t ask the rich to pay more. Moderately encouraging...

* Obama to aggressively defend liberal governance? Howard Fineman reports: “Obama will offer viewers and voters a strong defense of the moral role of government.” Also encouraging...

* Setting the bar for Obama: Jonathan Cohn sets the bar at a good place: If Obama isn’t willing to delve into specifics, at a minimum he must frame the budget as a “test of our priorities” and make a “principled, moral case for shared sacrifice.”

* Obama will claim mantle of bipartisanship — for his own vision: An apt prediction from Steve Benen: “the president will present a very different vision, and make it seem like it’s the Simpson-Bowles plan.”

* Ceding turf to GOP could cost Dems their base: The Post has a big article that gets at the heart of why the left is angry over Obama’s handling of the spending wars: He has thus far agreed to fight the battle largely on the GOP’s turf.

* Public prefers Obama’s approach to GOP’s: A new CNN poll suggests Obama may have an edge in the coming spending wars: The public favors Obama’s approach to cutting the budget while maintaining needed federal programs, 48-43.

Also interesting: Sixty eight percent think the GOP’s approach “unfairly favor some groups more than others,” which also suggests Dems should make the debate about priorities. But: A majority doesn’t think GOP proposals go “too far,” suggesting the Dem message about GOP extremism is not resonating.

* Dems determined not to be united on Social Security: A handful of Senate Democrats is signaling an openness to raising the retirement age, despite Harry Reid’s' strong opposition, indicating in advance that Dems won’t have a united front on “entitlements.”

* Better Dem messaging on Medicare needed: Joan McCarter suggests: “It’s the narrative Obama should adopt for tomorrow’s speech: In privatizing Medicare, Republicans want to dismantle it.”

* Medicare history lesson of the day: Andrew Leonard traces the history of conservative opposition to medical reform all the way back to 1964, a reminder that what we’re seeing today is only the latest chapter in a decades-long ideological struggle.

* And Romney takes a shot across Trump’s bow: In a gutsy act of leadership that could cost him support from the GOP base and give Donald Trump a major issue to use against him in the 2012 primary, Mitt forcefully stands up for the president’s citizenship.

What else is happening?