When Hillary Clinton announced last week that she had selected Senator Tim Kaine to be her vice presidential running mate, the reaction was fairly muted. The consensus was that Kaine was a safe pick, one that didn’t exactly light a fire in the bellies of voters, but probably wouldn’t hurt the campaign.

There is one group, though, that was fairly turned off by the pick -- progressive Democrats.

The left wing of the Democratic Party is already less-than-enthusiastic about the top of the ticket, and there was some hope that Clinton would appeal to Bernie Sanders supporters by picking a dyed-in-the-wool progressive as her running mate. Elizabeth Warren, Sherrod Brown, and Al Franken were all considered possibilities.

Kaine, though, is not a progressive. Left wing voters point to his record on a number of issues and wonder if he is more of a moderate than Clinton.

For one, the Virginia senator has been tepid on social issues for most of his career. He was especially slow to evolve on the issue of gay marriage, something he has in common with Clinton. As a practicing Catholic, Kaine is somewhat wishy washy on abortion rights. He claims that while he is personally opposed to the procedure, he supports a woman’s right to choose.

Then there’s trade, a key issue for many on the left. Kaine is a free trader, and he has expressed support for the Trans Pacific Partnership. The proposed free trade deal, supported by the Obama administration, has become a sticking point for many on the left, and chants of “No TPP!” have rung clear throughout the convention hall this week in Philadelphia.

Support for the financial industry is also a sticking point. As recently as this month, Kaine has called for deregulation of banks. The Sanders wing of the party spent much of the primary season calling out Clinton for her ties to Wall Street; picking Kaine doesn’t ease those concerns.

There are other problems too, like concerns about large, legal gifts Kaine accepted while he was governor of Virginia.

Given all this, Kaine has one simple job on Wednesday night -- convince voters on the left that he is an adequate choice to represent them, and that Clinton is as well. Look for him to focus on his time as a civil rights attorney and his record taking on the National Rifle Association. And, of course, Kaine will likely praise Clinton’s work on behalf of children and families, as has been the theme for much of the week.

Kaine can’t win the election for Clinton, but if he can use his speech on Wednesday to convince progressive voters that he isn’t a reason to abstain from voting for her, he will have done his job.

See original article on Fortune.com

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