Will Hillary's econ speech bring together Democrats?

Hillary Clinton will take a big step into the Wall Street policy world on Friday with a speech at New York University in which she will suggest raising capital gains taxes on investors who hold shares for less than a couple of years.

Clinton also plans to criticize other elements of what she calls "quarterly capitalism," including the current pace of corporate share buybacks and the tactics of activists like Carl Icahn who pressure executives to return cash to shareholders instead of invest it in new plants, equipment, research and employees.

The NYU speech will not be Clinton's big "taking on Wall Street" moment, aides tell me. That will come later with remarks on addressing so-called "Too Big to Fail" banks and punishing corporate crime.

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Hillary Clinton
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The Friday speech instead is intended, in part, to wed two wings of the Democratic Party that are miles apart right now, the "growth" wing and the "fairness" wing. Fairness Democrats, who thrill to the every word of Elizabeth Warren and Bernie Sanders, want higher taxes on the rich, strong new Wall Street reform and a relentless focus on economic inequality. Growth Democrats, who you don't hear much from anymore, want some of this, too, but prefer a focus on economic policies aimed at growing the pie rather than redistributing the slices.

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The Friday speech will be remarkably wonky for a presidential candidate and will reflect a policy approach favored for years by the likes of veteran Democratic wonks Gene Sperling and Neera Tanden. It's not often you will hear a major presidential candidate going into significant detail on share buyback transparency. But I'm told Clinton began to focus on the problem of slack corporate investment last fall and has been drilling deep into the details for months.

The address is intended to focus on long-term growth by trying to encourage buy-and-hold investing and taking pressure off corporate managements to focus on quarterly earnings per share targets at all costs. And it is intended to appeal to fairness Democrats by raising some capital gains taxes paid by top earners while also taking some shots at CEO pay and "hit-and-run" hedge funds.

The speech may fail to thrill the Warren crowd because Clinton is not likely to pitch the approach as a way to raise significant new revenue for the government. Instead she may suggest that increased revenues could be used for other incentives in the tax code to encourage business investment over buybacks and dividends.

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Still, she won't suggest lowering capital gains for investors who hold for very long periods, something many growth Democrats favor but the left would sharply reject as a tax cut for the very wealthy.

Clinton's formal and informal advisers acknowledge that tinkering with capital gains rates will not instantly solve the problem of "quarterly capitalism" or the lack of significant business investment. But they view it as a smart approach to take what is already a graduated scale for capital gains and tilt it more toward long-term holdings. And it is just the start of what will be a series of speeches aimed at using both government levers and political persuasion to alter the focus of corporate America.

"This is a theme she has identified and she clearly wants to orient the economy toward long-term growth and investment," Austan Goolsbee, a University of Chicago professor and former senior economic adviser to President Barack Obama, told me this week. "and this is a solid, market-based approach to doing that."

—Ben White is Politico's chief economic correspondent and a CNBC contributor. He also authors the daily tip sheet Politico Morning Money [politico.com/morningmoney]. Follow him on Twitter @morningmoneyben.