And yes, Judi, absolutely. This will only further erode his support from UCR voters, which are around a third of the electorate.
A sizable faction within the UCR are already likely to vote for Roberto Lavagna as it is, and the Pichetto pick will only add to their ranks.
You know, the only thing still keeping many UCR voters in the "Let's Change" fold, is their intense hatred of Peronists - which, in turn, is about the only thing they have in common with the neo-con Macri.
Macri has long governed under the assumption that this shared hatred would allow him the UCR to be used as a kind of coolie, stoically taking him wherever he needed to go for next-to-nothing in return - and with their mouths shut.
And frankly, they've proven Macri right - placating his every whim, and suffering in silence as Macri ignored them more and more.
But this might the final straw for many UCR voters, even if the leadership still goes along. Their support for Lavagna will now intensify, and I wouldn't be surprised if Macri now ends up in 3rd place (behind Beto Fernández and Lavagna).
You know, If I didn't know better I'd almost say Macri is deliberately trying to guarantee he'll lose.
But then, and as anyone could've told him, his adopting Bushonomics already did that for him.

"Not in front of reporters, Ernesto": Former UCR leader Ernesto Sanz gives Macri a reassuring pat during the 2015 campaign.
Sanz was one of the architects of the "Let's Change" coalition, which joined the centrist UCR with the hard-right (and much smaller) PRO in what was meant to be a "merger of equals." Macri narrowly won mostly on the backs of UCR votes.
But in practice, Macri's PRO monopolized nearly all power once he took office, relegating the UCR (Argentina's oldest and 2nd-most popular party) to little more than a congressional rubber stamp.