Amy McGrath, a former Marine fighter pilot who built a formidable campaign war chest, emerged Tuesday as the Democratic nominee to take on Senator Mitch McConnell of Kentucky, fending off a challenge from the left that highlighted the party’s ideological divisions.

One week after the primary was conducted, The Associated Press declared Ms. McGrath the winner after a campaign that was shaped by the coronavirus pandemic and protests against racial injustice. She narrowly defeated Charles Booker, an African-American state lawmaker who harnessed anger over a pair of fatal shootings by the authorities in Louisville to roar into contention in the final weeks of the campaign.

Ms. McGrath, though, had raised over $40 million by the start of June and built up a sizable advantage even before Primary Day because many voters cast absentee ballots to avoid the polls and the risk of contracting the coronavirus. It was not clear until Tuesday that she had won because a number of Kentucky counties waited to ensure they had counted their many mailed-in ballots before releasing results.

She will face an uphill contest against Mr. McConnell, the Senate majority leader, in a state that President Trump carried by about 30 points four years ago.

I have a lot of respect of Charles Booker’s campaign but I think his surge came too late while McGrath’s campaign had early investments in the state. It’s now onto the general election. Click here to donate and get involved with McGrath’s campaign.