1966 United States House of Representatives election in Delaware

← 1964 November 8, 1966 1968 →

Nominee William Roth Harris McDowell Party Republican Democratic Popular vote 90,561 72,142 Percentage 55.77% 44.23%

County results Roth:      50–60%

U.S. Representative before election Harris McDowell Democratic Elected U.S. Representative William Roth Republican

The 1966 United States House of Representatives election in Delaware took place on November 8, 1966 to decide who would represent Delaware's at-large congressional district in the United States Congress.Incumbent representative Harris McDowell ran for re-election to a sixth term but lost to Republican challenger William Roth by 11 percentage points. Prior to the election the seat was regarded as being a safe Democratic seat. With the loss, Harris McDowell became the last Democrat to represent Delaware in the House until Tom Carper in 1982.

The election was held in middle of Democratic President Lyndon B. Johnson term. His party lost 47 seats in the House.

Incumbent Harris McDowell was a veteran Democrat^[1] and was expected to easily hold the seat.^[2] In 1964, he had won reelection by 13 points and over 26 thousand votes.^[3] McDowell had previously lost a re-election bid in 1956 before returning to the House of Representatives in 1958.^[4]

The election was held during the midterm election cycle of Democratic President Lyndon B. Johnson. Like with most cycles the President's party struggled, losing 47 house seats^[5] along with various governships and Senate seats.^[6]

• Harris McDowell (Democrat), incumbent representative seeking a sixth term^[4]
• William Roth (Republican), businessman and unsuccessful candidate for Lieutenant Governor of Delaware in 1960^[7][8]
• George W. Cripps (Republican), defeated in the primary^[9]

There was some effort from the Delaware Democratic Party to get McDowell to run again Republican Senator J. Caleb Boggs in the concurrent Senate election. McDowell declined opting to instead seek another term in the House.^[2] Prior to the election the seat was regarded as being safe for the Democrats.^[2]

Roth was challenged for the Republican nomination by George W. Cripps. During his primary run Cripps called for further engagement in Vietnam War.^[10] Cripps and Roth did not run negative campaigns advertisements and avoided attacking each other. At the Delaware Republican Party (GOP) state convention, Cripps withdrew from the race and endorsed Roth's campaign, describing him as "The kind of man we need in the Republican party." He subsequently won the nomination for Delaware's Auditor of Accounts.^[9]

During the campaign John J. Smith, a Republican candidate for the state legislature, claimed there were irregularities with voting registration. Smith asked the United States Department of Justice to investigate and monitor the election, but was rejected due to a lack of legal basis for the request.^[11] A report by the grand jury of New Castle County found that there was evidence of illegal activity.^[12]

A list of absentee voters was made available to select Democratic candidate including McDowell. No Republicans received the list, Delaware GOP chairman Clayton S. Harrison criticized this decision referencing the findings of the grand jury report. Reportedly, McDowell used the list to send out campaign materials.^[13]

The election took place on November 8, 1966, concurrently with various other elections. Roth defeated McDowell by around 11 percent of the vote. He received 97,268 votes, nearly 30 thousand more than McDowell's 67,281. Roth received second highest number of votes of any Republican candidate elected at-large, behind only incumbent Insurance Commissioner Robert A. Short.^[14]

Additionally, Roth won all three of Delaware's counties. His strongest showing was in New Castle County where he received 66,871 votes. McDowell's strongest showing was also in New Castle County where he received 49,718 votes. The closest was Kent County where Roth won by just 723 votes.^[15]

General election results^[14]

Party		Candidate	Votes	%	±%
	Republican	William Roth	90,561	55.77%	12.4
	Democratic	Harris McDowell (Incumbent)	72,142	44.23%	12.3
Total votes			162,703	100.00%
	Republican gain from Democratic

Following his victory Roth resigned from his position as a senior councilman at Hercules Inc.^[7] Like several other lame duck representatives after the loss McDowell was set travel to Europe as part of a parliamentary delegation.^[16] However, he, along with fellow Democratic representatives Roy H. McVicker and Ronald B. Cameron, decided to cancel their trips. When asked why McDowell explained that he did not think it was fair for a outgoing congressman to go abroad.^[17]

McDowell and Roth would again compete in the following 1968 election, Roth once again won increasing his margin of victory to seventeen percent.^[18] During his second term, Roth resigned from the House to fill a vacant Senate seat.^[8] He was succeeded by Republican state representative Pete du Pont.^[19] With the loss McDowell became the last Democrat to represent Delaware in the House until Tom Carper's 1982 victory.^[15][20] After his defeat, McDowell was appointed to a position within the Government of Delaware by then-Governor Charles L. Terry Jr..^[7] Despite this, during the following election Terry endorsed candidates to run against McDowell in the Democratic primary.^[21]