In the Senate, McNary helped to pass legislation that led to the construction of Bonneville Dam on the Columbia River, and worked on agricultural and forestry issues.

They lost to the Democratic ticket, composed of Franklin D. Roosevelt, who was running for his third term as president, and Henry A. Wallace, by just under a ten-point margin.

[6] In the autumn of 1896, McNary moved to California to attend Stanford, where he studied law, economics, science, and history while working as a waiter to pay for his housing.

[9] He recruited prominent local attorneys to serve on the faculty and increased the size of the school from four graduates in 1908 to 36 in 1913, his last year as dean.

[9] In his drive to make Willamette's law school one of the top programs on the West Coast, he had it re-located from leased space in office buildings to the university campus.

[12] She had been in Oregon to attend the funeral of her mother and was returning from Portland in the Boise family's car when it flipped and crushed her.

[13] After West won the election, he chose McNary to be special legal counsel to Oregon's railroad commission; he urged lower passenger and freight rates.

[16] A supporter of organized labor, McNary "consistently defended the rights of injured workers and was not hesitant about using the bench as an instrument for social change",[17] such as an eight-hour day for public employees.

The dissent was described as emotionally charged and "revealed a deeply seated personal discomfort with same-sex eroticism".

[15] At that time the office was partisan, and McNary lost the Republican primary, by a single vote, to Henry L. Benson, after several recounts and the discovery of uncounted ballots.

[19] On July 8, 1916, after a close, multi-ballot contest, with several contenders, the Republican State Committee elected McNary to be its chair.

[21] When US Senator Harry Lane died in office, on May 23, 1917, McNary saw a chance to redeem himself after his failed bid for election to the Oregon Supreme Court.

[23] The governor preferred someone who supported national women's suffrage and Prohibition, and he shared with McNary an interest in farming.

[12] In the November general election, he defeated Oswald West, a friend and former governor, by 82,360 to 64,303, to win a full, six-year term in the Senate.

[12] Meanwhile, Frederick W. Mulkey won the election to replace McNary and finished Lane's original term, which would end in January 1919.

Because the treaty included provisions for establishing and joining the League of Nations, one of Wilson's Fourteen Points, Republicans opposed it.

[26][27] Going against much of his party, McNary, part of a group of senators known as "reservationists", proposed minor changes to support the United States entry into the League.

[25] The friendship helped McNary secure favorable committee assignments and ushered him into the inner power circle of the Senate.

[3] He voted to keep an arms embargo in place but supported the Lend-Lease agreement with the British in 1941 and the reinstatement of Selective Service in 1940, in preparation for military conscription of civilian men.

"[3] McNary's acceptance speech reiterated his support for the Tennessee Valley Authority,[32] a federally owned power-producing corporation that Willkie, as "the head of a far-flung [private] utilities empire", had opposed.

[3] During the campaign, McNary promoted farming issues and criticized foreign trade agreements, which, he said, had "closed European markets to our grain, meat, fruits and fiber".

He met Morton at a dinner party during World War I, in her hometown of Washington, D.C.[34] Before the marriage, she had worked as his private secretary.

[34] His estate, called "Fir Cone", featured a putting green, rose garden, tennis court, fishpond, and arboretum, and more than 250 acres (1.0 km2) of trees.

[36] Fir Cone was described as Oregon's Monticello by later Senator Richard L. Neuberger, as it hosted many meetings with politicians from the national stage.

[34] The farm included 110 acres (0.45 km2) of nut and fruit orchards, through which McNary helped establish the filbert industry in Oregon[9][37] and on which he developed the Imperial prune.

[3] After complaining of headaches and suffering slurred speech beginning in early 1943, McNary went to the Bethesda, Maryland, Naval Hospital on November 8, 1943, where doctors diagnosed a malignant brain tumor.