As Ms. Day sings, “We’ll walk it out together now,” the commercial shows a number of victims of gun violence and racial attacks who are supporting Mrs. Clinton: Representative John Lewis, Democrat of Georgia, who was famously beaten in the 1965 Selma-to-Montgomery march; Geneva Reed-Veal, the mother of Sandra Bland, who was found hanged in a Texas jail cell after being arrested during a traffic stop last year; and Gabrielle Giffords, the former Arizona congresswoman who was shot in the head in 2011 and has become a powerful advocate for expanded gun control.

The ad closes with warm images of Mrs. Clinton one-on-one with avid supporters and beaming in front of a big crowd, as a concluding message fills the screen: “Let’s stand together.”

Impact

Mrs. Clinton’s campaign, like Mr. Sanders’s, has long alternated between emotional ads that engage in identity politics and policy-driven commercials on issues like equal pay, health care and money in politics. This ad may be her first — and certainly is the most effective — to touch on the “love and kindness” theme that she has been sounding on the campaign trail for months.

Takeaway

Like a salve after an unexpectedly injurious Democratic primary, the “hope and love” message looks beyond Indiana, California and other remaining primaries. Ms. Day’s lyric — “We’ll walk it out together now” — and the ad’s appeal to “support each other” are consistent with Mrs. Clinton’s need to persuade Sanders supporters to heal their differences with Mrs. Clinton and unite behind her if and when she seals up the Democratic nomination.

Changing channels …

Howler

The Trump campaign, newly focused on advertising and spending about $1 million in Indiana alone, released an ad leveling numerous attacks against Senator Ted Cruz, all which could be rated “half-true.” It accuses Mr. Cruz of supporting amnesty for immigrants in the country illegally, on which his stance has shifted; of supporting President Obama’s trade bill, which he actually opposed once it was drafted; and of favoring the admission of Syrian refugees, which Mr. Cruz did in 2014, but has adamantly opposed since late last year.