“Politics stops at the water’s edge” is an old political adage, credited to several politicians. The phrase means that, in regards to foreign affairs, the United States is united and bipartisan. Alf Landon (1887-1987), unsuccessful Republican candidate for president in 1936 against Franklin D. Roosevelt, used the phrase often in 1936 and 1937. Michigan Republican Senator Arthur Vandenberg used the phrase in the 1940s and 1950s.
 
Daniel Webster (1782-1852), while encouraging men to enlist in 1814 (during the War of 1812), said it first:
 
“Even our party divisions, acrimonious as they are, cease at the water’s edge. They are lost in attachment to the national character, on the element where that character is made respectable. In protecting naval interests by naval means, you will arm yourselves with the whole power of national sentiment, and may command the whole abundance of the national resources.”
   
   
Wikipedia: Daniel Webster
Daniel Webster (January 18, 1782 – October 24, 1852) was a leading American statesman during the nation’s Antebellum Period. He first rose to regional prominence through his defense of New England shipping interests. His increasingly nationalistic views and the effectiveness with which he articulated them led Webster to become one of the most famous orators and influential Whig leaders of the Second Party System.
 
Daniel Webster was an attorney, and served as legal counsel in several cases that established important constitutional precedents that bolstered the authority of the Federal government. As Secretary of State, he negotiated the Webster-Ashburton Treaty that established the definitive eastern border between the United States and Canada. Primarily recognized for his Senate tenure, Webster was a key figure in the institution’s “Golden days”. So well-known was his skill as a Senator throughout this period that Webster became the northern member of a trio known as the “Great Triumvirate”, with his colleagues Henry Clay from the west and John C. Calhoun from the south. His “Reply to Hayne” in 1830 was generally regarded as “the most eloquent speech ever delivered in Congress.”
   
Wikipedia: Alf Landon
Alfred “Alf” Mossman Landon (September 9, 1887 – October 12, 1987) was an American Republican politician, who served as Governor of Kansas from 1933–1937. He was best known for being the Republican Party’s nominee for President of the United States, defeated in a landslide by Franklin D. Roosevelt in the 1936 presidential election.
 
wiseGEEK
What Does “Politics Stops at the Water’s Edge” Mean?
Imagine picking a fight with your spouse at a new acquaintance’s home, or even at your parents’ house, or the home of a friend. Manners prescribe that we do not do this, or “air our dirty laundry in public.” Personal disputes, like those we may have in our relationships, are generally held to have little place when we’re in public.
 
This same principle is implied in the statement, “Politics stops at the water’s edge,” first suggested by Republican Senator Arthur Vandenberg in 1952. The idea was widely adopted under the Truman administration by the US. Vandenberg is recognized for abandoning his isolationist views of American foreign policy in favor of a more international view, and he worked in a bipartisan way to gather support for things like the creation of NATO. One of his principal statements was that American politicians should always present a united front to other countries, despite political disagreements on their own turf. To air these disagreements at events aimed at internationalism weakened America’s show of strength. Thus politicians visiting elsewhere took on the doctrine that politics stops at the water’s edge, since raising partisan disputes would not best represent the united front of a strong, whole America.
 
Vandenberg certainly wasn’t implying that politics stops at the water’s edge meant stopping partisanship within the US. Just as couples can fight it out in their own backyard, so can senators, presidential candidates and the like. But many have felt that events in the US, particularly in the 2000s, have led to increased violation of the rule that politics should stop at the water’s edge.
 
Google Books
The Writings and Speeches of Daniel Webster
Volume One
Boston, MA: Little, Brown & Company
1903
Pg. 31:
Even our party divisions, acrimonious as they are, cease at the water’s edge. They are lost in attachment to the national character, on the element where that character is made respectable. In protecting naval interests by naval means, you will arm yourselves with the whole power of national sentiment, and may command the whole abundance of the national resources.
(A speech encouraging enlistments in 1814—ed.)
 
Google Books
The Republican Party:
A History of its Fifty Years’ Existence and a Record of its Measures and leaders
1854-1904
By Francis Curtis
Vol. II
New York, NY: G. P. Putnam’s Sons
1904
Pg. 311:
We should be able to say, as Webster said in the House of Representatives, that our politics stop at the water’s edge, and that when we come to dealing with a foreign question we deal with it simply as Americans.
 
22 June 1919, Fort Wayne (IN) Journal-Gazette, pg. 23, cols. 2-3:
The speaker also quoted an appeal of former President Taft, against the Knox resolution, in which Mr. Taft urged that politics should stop at the waters’ edge.
 
“I agreed with that perfectly”, continued Mr. Borah. “Does politics stop at the waters’ edge regarding the Montoe doctrine? Yes, but on this side of the water. And so with a multitude of other things in this covenant. It is inconceivable that this can be kept out of politics, for the people have no way to express themselves except through political parties.”
   
11 July 1928, Muscatine (Iowa) Journal and News-Tribune, “Concerning the Advisability of Keeping the Campaign at Home,” pg. 3, col. 2:
Aside from that it may be suggested to responsible democratic campaign managers that if this campaign stops at the water’s edge there will be distinct advantage in it for the country at large.
 
19 August 1936, Ames (Iowa) Daily Tribune-Times, pg. 4, col. 1:
Present legal ownership stops at the water’s edge.
 
21 December 1937, Tyron (PA) Daily Herald, pg. 1, col. 7:
Washington, Dec. 21 (INS)—Peace is the ultimate goal of the American people, but it cannot be assured “by closing our eyes to the fact that whether we like it or not we are a part of a large world,” President Roosevelt said today in a telegram to Gov. Alf M. Landon, his opponent for the presidency in 1936.
 
The President’s telegram to Gov. Landon was in reply to a message which the Kansan sent him, pledging anew his support of the administration on its foreign policy. So far as he is concerned, Landon’s message state, “politics cease at the water’s edge.”
 
17 November 1938, El Paso (TX) Herald-Post, pg. 4, col. 1:
Mr. Landon, as everybody knows, was Mr. Roosevelt’s opponent in the 1935 elections. He was decisively beaten. But instead of retiring to the sidelines to jeer, more than once he has emerged to join whole-heartedly in the cheers. When the Japanese sent the panay to the bottom of the Yangtze, he went out of his way to back up the Administration’s stand, saying that, in America, politics stops at the water’s edge.
   
12 December 1938, El Paso (TX) Herald-Post, “Landon Backs Hull’s Hemisphere Defense Policy 100 per Cent” by William Philip Simms, pg. 1, col. 6:
Mr. Landon’s gesture, therefore, gains added significance. It parallels closely his stand at the time of the sinking of the American gunboat Panay by Japanese troops in the Yangtze River, when he supported the Administration’s policy and said that “politics stops at the water’s edge.”
     
Google Books
Blood Is Cheaper Than Water:
The prudent American’s guide to peace and war
By Quincy Howe
New York, NY: Simon and Schuster
1939
Pg. 76:
Even Alfred M. Landon announced in December, 1937, “Politics cease at the water’s edge.”
     
Google Books
The American Stakes
By John Chamberlain
New York, NY: Carrick & Evans,Inc.
1940
Pg. 145:
At the Water’s Edge POLITICS, said Alf Landon in an all-too-quotable line, should stop at the water’s edge.
 
17 October 1940, Cumberland (MD) Evening Times, pg. 4, col. 2:
It is more important now than it has been for decades for partisans on both sides to play fair, keep their words and deeds under control, and remember the American tradition, that “politics stops atthe water’s edge.”
 
30 September 1941, Sheboygan (WI)

, pg. 20, col. 2:
By supporting the foreign policy, by taking it for granted that politics stops at the water’s edge, the republicans have no explanations to make .
 
9 January 1943, Wisconsin State Journal (Madison, WI), “America Must Not Reject Trade Program” by Raymond Clapper, pg. 4, col. 4:
This war is big enough, and the job of steering through the chaos of peace will be hard enough, so that there will be work and credit for all to share regardless of party. This is certainly the time to follow the old American tradition that politics stops at the water’s edge.
 
13 September 1946, Lubbock (TX) Morning Avalanche, pg. 12, col. 3:
It is often said that politics in the United States stops at the water’s edge.
 
14 May 1956, Big Spring (TX) Daily Herald, pg. 4, col. 1:
There is a saying in Britain that its foreign policy stops at the water’s edge, the meaning being that however much Tory and Liberal may wrangle over domestic affairs, they see eye to eye on foreign affairs.
     
Google Books
Landon of Kansas
By Donald R. McCoy
Published by University of Nebraska Press
1966
Pg. 378:
Referring to his statement at the Gridiron Club in 1936 that “politics end at the water’s edge,” Landon said: It means there must be no demagogic playing of…
 
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Water’s Edge: domestic politics and the making of American foreign policy
By Paula Stern
Published by Greenwood Press
1979
 
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Hatchet Jobs and Hardball: the Oxford dictionary of American political slang
By Grant Barrett
Published by Oxford University Press US
2004
Pg. 287:
water’s edge n. the boundary (geographical and figurative) between domestic policy (esp. elections) and foreign policy.
1939 Helena Independent (Mont.) (Sept. 23) 4:
However, those sentiments demonstrate one thing—that politics stops at the water’s edge when a menacing problem present itself from outside.
1946 New York Times (Oct. 7) 4:
President Truman’s latest statement on Palestine illustrates the influence of domestic politics on United States foreign policy and demonstrates the limitations of the theory that politics stops at the water’s edge.
1950 New York Times (Apr. 9) E1:
Since the war a guiding principle in America’s approach to foreign policy has been: “Politics stops at the water’s edge.”
2003 Wall Street Journal (Aug. 20) A10:
Mr. Reagan’s conservatism didn’t end at the water’s edge. Despite enormous opposition from congressional Democrats, he pushed back the Soviet Union on all fronts.
2003 New Pittsburgh Courier (Sept. 24) A7:
As for the cliche “Politics stops at the water’s edge,” an old Washington Post editor, Felix Morley, had the best answer: politics stops at the water’s edge only when policy stops at the water’s edge.
 
Google Books
At the Water’s Edge: American Politics and the Vietnam War
By Melvin Small
Published by Ivan R. Dee
2005
     
Real Clear Politics
December 08, 2006
The War at Home
By Daniel Henninger
(...)
These are essentially restatements of GOP Sen. Arthur Vandenberg’s 1952 dictum amid the Truman presidency that “politics stops at the water’s edge.” More than a sentiment, Vandenberg’s point was, as he put it, “to unite our official voice at the water’s edge so that America speaks with maximum authority against those who would divide and conquer us.” For the past three years, we have had the opposite—a domestic political war waged relentlessly at the water’s edge.
   
Google Books
Safire’s Political Dictionary
By William Safire
Edition: revised
Published by Oxford University Press US
2008
Pg. 796:
water’s edge Where some believe that partisan politics, in the interest of national foreign policy, is supposed to stop.
(...)
The phrase is closely linked to a BIPARTISAN foreign policy. Architect of that policy, Michigan Republican Senator Arthur Vandenberg, whose 1945 Senate speech marked his repudiation of isolationism, used it in his own 1950 definition to a constituent: “To me ‘bipartisan foreign policy’ means a mutual effort under our indispensable two-party system to unite our official voice at the water’s edge.” “What mainly stops at the water’s edge,” countered historian James MacGregor Burns, “is not party politics in general but congressional party politics in particular. The real ‘UNHOLY ALLIANCE’ to a good congressional Republican is the historic coalition between the internationallists in both parties.”