Richard H. White writes :
Upon the resignation of Governor William G. Brownlow on February 25, 1869 to assume the duties of United States Senator on March 4, Mr. Senter as Speaker of the State Senate succeeded to the governorship of Tennessee. He had served in the Legislature both before and after the War Between the States. In politics, he was a conservative Unionist. Inasmuch as he was elevated to the chair of Chief Executive “by inheritance,” quite naturally he desired to serve in that capacity by a direct election by the people. Accordingly, he let it be known that he would be a candidate to succeed himself in the August primary only some five months distant. When the Union Convention (now called Republican) met in May, 1869, for the purpose of nominating a gubernatorial candidate, the Convention split wide open. The Conservatives favored Governor Senter, while the Radicals espoused the cause of an ultra Radical, Congressman William B. Stokes. For two days, the wrangling between the two factions continued with unabated fury, with the result that the Convention actually was never organized. No Chairman was seated, no organized business was conducted, and no nomination by the Convention was sanctioned. The end-result of the abortive effort was that each faction named its favorite, the Conservatives supporting Senter while the Radicals flocked around the standard of Stokes.
In a joint campaign, covering the State, the two candidates slugged it out in what was perhaps the most bitterly fought gubernatorial contest ever waged in the Volunteer State. Repeated attacks upon each other’s political record, involving at times unsavory personal slurs and accusations, consumed most of the time on the hustings. The only real issue that developed was that of the elective franchise. Senter proposed removing the shackles that had been placed upon all ex-Confederates by the Brownlow regime, while Stokes refused to make any such outright declaration.
The election laws that had been passed during the Brownlow administrations gave the Governor unprecedented power. He appointed all local election officials, and was vested with the power to throw out any election results that in his opinion had not been conducted according to the ironclad rules and regulations. These election laws had clothed the Governor with dictatorial powers. As the result of a decision by the Tennessee Supreme Court in April, 1869, it was declared that Commissioners of Elections appointed by the Governor had no tenure of office fixed by law and were subject to removal by the Governor. It was upon this basis that Senter removed some three-fourths of the Radical Election Commissioners and appointed Conservatives in their stead. This action opened the ballot box to former ex-Confederates who had been disfranchised. Inasmuch as the latter group, comprising the bulk of the Democratic Party, had entered no candidate in the gubernatorial race they naturally voted for Senter, resulting in Senter’s election over Stokes by a majority of approximately 65,000 votes.
The above action by Governor Senter broke the strangle-hold of the Radicals in Tennessee. The domination of the Radicals had come about as a result of the War Between the States whereby the exConfederates through Brownlow laws had been denied participation in the election of public officials. Senter favored the restoration of the franchise to this large group of citizens constituting a healthy majority in the State as a whole. Directly through his action, Radical domination in Tennessee politics came to an end.
Governor Senter assumed the duties of his high office at a trying time. It would have been easy enough to have mounted the Car of State and continued to ride down the inclined plane to a speedy ruin already then in sight. But to give the signal to apply the brakes, to check the speed, and to reverse the engine without a crash - this required a steady nerve and a clear brain. These prerequisites Senter possessed. In his campaign for election, he advocated the calling of a Constitutional Convention. The Democratic Legislature which was elected along with Senter agreed with him, and delegates were elected in December, 1869, met in January, 1870, and the Constitution of 1870 was prepared in a few weeks and subsequently ratified by the people. Once more, democracy in State and local government had been restored.
After his retirement from the office of Governor, it appears that Senter took no further active part in politics or public affairs. He died at Morristown on June 14, 1898, and was buried in the old City Cemetery. Years later, his ashes were removed to the Jarnagin Cemetery in Morristown and a befitting monument marks the location of his grave.*

A quote from the Tennessee State Library and Archives website :
“As speaker of the senate he became governor when Brownlow left office to go to Congress. He won the election later that year by an overwhelming majority. He took office at a time when many citizens could not participate in the governmental process because of their involvement with the Confederate cause. His administration faced the rise of the Ku Klux Klan and its terrorism of the entire south. The most important event of Senter’s administration was the Constitutional Convention of 1870, resulting in the constitution now in use. Black suffrage was achieved, but along with it a poll tax that would keep many blacks from voting for years.”