James Henry Davidson (June 18, 1858 – August 6, 1918) was an American lawyer and Republican politician from Oshkosh, Wisconsin.

As a child, he attended the district schools in the Winters and worked on his father's farm, or joined him lumbering in the nearby woods the rest of the year.

Through his employment with Elmer D. Morse, then one of the most important businessmen in the city, he was quickly able to repay his debt for his school loan.

A short time later, he moved to the larger neighboring city of Oshkosh, Wisconsin, where he expanded his legal practice.

[4] At the time, the 6th congressional district comprised Davidson's home county, Winnebago, plus Calumet, Manitowoc, Fond du Lac, Marquette, Green Lake, and Waushara.

[5] Davidson was appointed to the House Committee on Rivers and Harbors, which allowed him to play an important role in appropriating funds for projects relevant to his part of the state.

[6] When running for re-election, Wisconsin newspapers remarked that Davidson had a notable first term, and was diligent and attentive to constituent services and issues of local concern.

[14] An emergency ruling of the Wisconsin Supreme Court ultimately determined that write-in primary candidate John E. McMullen would be considered the official nominee of the Democrats in the district and ordered his name to appear on the ballot,[15] but McMullen did not actively campaign for the seat, and Davidson easily won his sixth term.

[17][18] Until 1912, Davidson largely avoided the bitter intra-party Republican feud of this era between progressive and stalwart factions.

In 1912, however, he firmly endorsed the campaign of Wisconsin's progressive U.S. senator Robert M. La Follette seeking the Republican nomination for the presidency.

Davidson did not leave the Republican Party, but ran a series of large newspaper advertisements that sought to make clear he considered himself a "progressive".

Davidson easily won the three-way contest,[25] but lost the general election rematch to Reilly by a narrow margin.

[27] In their third matchup, Davidson finally defeated Michael K. Reilly in the 1916 general election and reclaimed his seat in the House of Representatives.

[28] During the 1916 campaign, Davidson ran on a platform of strict neutrality in World War I, and stuck to that position after his election.