Roblin was a part of the latter group and was elected to the Legislative Assembly of Manitoba in 1949 as an "Independent Progressive Conservative" opposing the coalition.

Running in the multi-member riding of Winnipeg South, he finished well ahead of the official Progressive Conservative candidate and soon emerged as the leading voice for anti-Conservatives in the province.

Willis resigned as a cabinet minister in August 1950, and the Progressive Conservative delegates overwhelmingly voted to leave the coalition at their annual convention that year.

His government lost a parliamentary vote of confidence in 1959, but was re-elected with a decisive majority in the ensuing election later in the year, taking 36 out of 57 seats.

Roblin's government upgraded highways, created parks, and built the Red River Floodway around Winnipeg, popularly known as "Duff's Ditch."

It also improved postsecondary education and promoted urban development by consolidating the various municipalities in the Winnipeg area into a single metropolitan entity.

For primary education, Roblin's ministry brought Manitoba's system of one-room schoolhouses into the modern era by building consolidated schools.

Roblin was hurt by an unpopular provincial sales tax introduced by his government as well as the more general "Trudeaumania" phenomenon.

In 1978, Roblin was appointed to the Senate by Prime Minister Pierre Trudeau, officially representing the Manitoba region of Red River.

Roblin, a veteran of World War II who fought in the Normandy Campaign, represented Manitoba at the 60th Anniversary of D-Day in France.

He brought Manitoba into the modern era, with desired changes in education, hospital finance, roads, social assistance and flood protection.