With his selection of Kamala Harris, Joe Biden bowed to the inevitable. Harris ticks all the boxes — Bay Area progressive who pushed a lock ’em up policy, senator with no apparent skeletons that haven’t already been pulled out of the closet (see: Willie Brown), and a woman and minority who relishes political brawls. She once bashed Biden for his busing policy. Now she will be busing him.

Harris has it all over the other candidates. Karen Bass of El Jefe and Venceremos Brigade fame was a disaster waiting to happen. Susan Rice is a creature of Washington elite institutions with no real political constituency. And Stacey Abrams would have driven away the very moderates that Biden is so assiduously wooing.

Harris, by contrast, allows Biden to show that he is ready to usher in a new Democratic party that has the tincture of progressivism but no more. He wants to occupy not the high but the middle ground. Harris, who was born in 1964, will bring high-octane energy to the ticket. Biden is also showing a certain magnanimity, allowing bygones to be bygones over the slurs that Harris hurled at him over school busing during the primary debates.

In a sense Biden must also have been impressed by Harris’s skill at trashing her opponents. The slings and arrows were once aimed at Biden by Harris. Now Harris will be aiming them at Trump, no slouch himself at the art of objurgation. Trump will relish the opportunity to lash into Harris, but the more he does the less he will be focusing on Biden himself. Harris is no Tim Kaine, who could barely cope with Mike Pence in 2016. She’s ready to rumble. Trump and Pence should beware.