Dallas Historical Election and Spending Well

I am writing from Dallas, where yesterday elections created yet another surprise. Mr. Watkins has become the first African American Attorney General of Dallas country. He has defeated Republican Toby Shook. It is interesting to observe that Mr. Shook campaign has been much better funded than that of Mr. Watkins. As a matter of fact he spent 25 to 1 more than Mr. Watkins whose campaign raised a fraction of money Mr. Shook managed to have. From an economics point of view this is indeed interesting.

If we consider winning in an election the outcome determined by a production function, which is function of capital and labor, the question would be where the marginal gain of raised funds starts to diminish. Campaigns raise money in order to fund their activities in order to have the votes to win, thus the marginal benefit of each dollar raised is the number of votes that it adds to total existing votes. After a certain value of funds being raise the number of votes that an extra dollar brings in declines and diminishing returns begin. This continues until the number of vote stops increasing because of increasing funds and marginal benefit of a raised dollar becomes zero. Thus having access to large funds helps but does not guarantee the results I wonder what is in literature regarding this.