Wasn’t it cute? Hillary Clinton and Elizabeth Warren looked like twins the other day in Cincinnati: Same blond bob haircut, bright blue blazers, white-hot rhetoric and matching grins when they excoriated Donald Trump.

Which is exactly why Warren will not get the vice presidential slot on Clinton’s ticket.

Clinton does not want a twin running mate. And while she needs Warren to help solidify the Democratic vote this summer, Warren could be less helpful in the general election.

Warren was the only female senator who did not endorse Clinton until it was painfully obvious Bernie Sanders was whistling in the wind. Friends of Hillary is a special club you cannot join too late.

Warren is on board now because there is nowhere else for her to go to stay viable in the party. She is doing such a good job and proving to be such an effective attack dog against Trump that Hillary will be able to choose someone else as her running mate.

Is the country ready for two women on the same ticket? Probably, but why, if you are cautious Hillary, would you take the chance in what is likely to be a very close election?

The governor of Massachusetts, Warren’s home state, is Charlie Baker, a Republican, and he’d appoint a Republican to fill Warren’s seat if she became vice president. Too risky.

Also, Massachusetts will vote Democratic anyway. On the other hand, somebody “safe,” such as Tim Kaine, the Democratic senator from Virginia, not only could deliver a key state to Clinton but would be succeeded by a Democrat appointed by Democrat Gov. Terry McAuliffe.

If Clinton becomes president, she desperately needs a Democrat-controlled Senate to get anything done in her first 100 days. No matter who the next president is, Washington will still be politically divided; Republicans won’t want to cave to a Democratic agenda and there is no way Democrats will agree to almost anything Trump has been proposing.

A major reason against putting Warren on the ticket is the antipathy she has earned from her outspoken criticism of Wall Street and her work setting up the Consumer Finance Protection Board. She is viewed as too liberal for many business leaders.

While Warren is beloved by the progressive Democratic base, Hillary must win over some Republicans to win the White House, in part because the Libertarian Party candidate Gary Johnson and the Green Party candidate Jill Stein will cut into her votes as she fights Trump.

Warren also has no foreign policy experience, a telling weakness in the increasingly complicated global arena.

One of the vice president’s key attributes in modern times is to be able to work with Capitol Hill to try to bring about consensus. But Warren is considered too partisan and too much of a firebrand to fit into that role easily.

Kaine, who wants to run with Hillary, is ideologically closer to her than Warren is, and he has immersed himself in foreign policy issues in the Senate. He was also governor of Virginia, giving him executive experience. Kaine also would not compete with Hillary or outshine her as the independent-minded Warren might tend to do.

If Warren stays in the Senate, she will be free to perpetuate her cause of fighting the 1 percent and financial inequality. On the ticket or off, no matter what, she will campaign hard against Trump.

This has been a year of turning conventional wisdom on its head. But Hillary, who will turn 69 just before the November election, is not known for taking unnecessary political risks.

Ann McFeatters is an op-ed columnist for Tribune News Service.