This situation was about to change, however, and with a Southerner in the White House, to the South’s distinct advantage.  Pres. Polk was never more effective in his duplicitous dealings with Congress than he was in inducing Congress to declare war on Mexico on May 12, 1846.  While his predecessor John Tyler had signed the bill annexing Texas with only three days left in his term in office, there was not agreement between Mexico and the U.S. on where the border of Texas actually was located.  Polk used this to his advantage to gain his real objective of conquering as much territory in Northern Mexico as possible for a variety of reasons, including: to connect the southern portion of the country with the Pacific Ocean, to gain new territory to expand the number of southern slave states to offset the population growth in the north, and to gain control over a southern route for a transcontinental railroad.  Knowing he faced stiff opposition from Whigs and Northern Democrats to this expansion, he needed to create a diversion as well as casus belli.  While he falsely let Northern Democrats believe that he supported the 1844 Platform plank that explicitly stated that the U.S. should settle only for all of the Oregon Country (“54° 40’ or Fight” – with more northern land, there would be more northern states and business), Polk had no intention of going to war with Great Britain and would eventually settle on the 49° parallel when the timing suited his overall strategy.  Meanwhile, he secretly instituted military plans and forces in Texas and California that, for the lack of immediate communications of the age, went off, aided by a little luck, with amazing clockwork timing:

-April 23, 1846: The Senate approved a resolution calling for the termination of the 1819 Joint Occupation treaty in response to a mistaken British rejection of a U.S. compromise of the 49° parallel, that reignited cries of “54°40’ or Fight!”

-April 24, 1846: Gen. Zachary Taylor sends a detachment of troops to the the Rio Grande to see if rumored Mexican forces have crossed “the Rubicon.”  They had, indeed, and proceeded to capture the Americans the next day: casus belli, (it will take two weeks for news of this to reach Washington)

-May 12, 1846: the Senate votes for war with Mexico

-May 13, 1846: Polk declares war on Mexico

-May 19, 1846: having tricked his opponents into declaring war on Mexico, Polk accepts a British compromise offer to end the Oregon dispute at the 49° parallel, to avoid a “two-front war.”

-June 18, 1846: the Oregon Treaty was not approved by Congress until, one month after war had been declared on Mexico.

Polk had planned for a quick war, underestimating the Mexican military.  Hostilities lasted for twenty-two months, ending with the Senate’s ratification of the Treaty of Guadalupe Hildalgo on March 10, 1848. Mexico ceded its northern states of Santa Fe de Nuevo México and Alta California, north of Gila River, to the U.S. Polk now had his continuous southern land route to the Pacific.

Map of U.S. following the Mexican-American War, 1846. (Online)


Early in 1846, Wisconsin was readying its application for statehood, enviously looking at Chicago’s renewed commercial success, and recalled that according to the original provisions of the Northwest Ordinance, Chicago and Galena were to have been within its borders.  The population contained in this area would more than assure that Wisconsin could meet the minimum of 10,000 needed to apply for statehood.  In addition, many of the towns in the disputed area, such as Rockford, where a mass meeting had been held in 1840 that supported the transfer of northern Illinois back to Wisconsin, felt more closely aligned to Wisconsin than to southern Illinois.  Wisconsin’s territorial representative made this argument to Congress in claiming that the new state’s borders should include all land originally allocated by Congress in 1787.  The two northern Illinois’ Representatives (Wentworth from Chicago and Joseph P. Hoge from Galena) were subsequently promised by Wisconsin’s leaders to be made the state’s first two U.S. Senators if they would support the move.  

As Wentworth later related, however, the canal once again saved Chicago for Illinois:

“Our Chicago people were much divided upon the question, and I really believe serious consequences would have grown out of it but for the embarrassments that would be caused by having the Illinois & Michigan Canal owned by two states.  As an original question, all the five states being out of the Union, there is no doubt that Congress would have enforced the provisions of the ordinance, and Illinois been cut off from the lakes, and her Legislature saved from the annoyance of Chicago lobbyists.  But might made right.”

Meanwhile, Wentworth had kept both the Chicago harbor and canal issues alive in Congress by raising the specter of British power on the Great Lakes during any future war, that in early 1846 was not unlikely, as the 1842 Webster-Ashburton Treaty had not resolved the Oregon border that allowed expansionists like himself, encouraged by Polk’s devious plan to passively support such action until he got his declaration of war with Mexico, to continue to pursue “manifest destiny” in Oregon with the chant of “54° 40’ or Fight”:

“Chicago is within two days travel of British troops by the thousands, and Canada is being overrun by them.  Our country must not, will not give up an inch of Oregon… Great Britain fears all this; and is preparing to resist it.  We must prepare also by opening the way for vessels from the great Naval Depot at Memphis to the Lakes.  -And now is the time.  In peace, prepare for war.”


Wisconsin’s unsuccessful play for Chicago was not, however, the only threat posed to completion of the canal at this time.  Unbelievably, just as construction on the Chicago canal was finally ready to resume in the fall of 1845, the Federal government once again stopped all funding for Chicago’s harbor improvements.  During the four years of depression from 1839 to 1843 during which no harbor appropriations were passed, the strong lake current had formed another sandbar at the mouth of the river, precluding vessels with deep draughts from safely entering the river. 

Map showing the growth of the sand deposits against of the north pier. (Andreas, History of Chicago-I)

In late 1842, the area’s Congressmen had finally succeeded in getting $25,000 approved for dredging the sandbar at the river’s mouth along with minor improvements done under the supervision of Captain George B. McClellan.  This had coincided with the arrival in Washington in March 1843 of the newly-elected Rep. John Wentworth, who succeeded in getting the 1844 appropriation increased to $30,000.

Early in 1846, Wentworth was one of the authors of the River and Harbor Bill of 1846, that earmarked over $500,000 for improvements to the harbors on the Great Lakes and the Hudson River, including $12,000 for Chicago’s harbor and $15,000 for a new steam dredge for Lake Michigan to replace the old Federal dredge that had sunk off Kenosha while being moved north.  The bill easily passed the House on March 20, before Polk’s Mexican scheme began, with the Senate concurring on July 24, 1846, after Polk had declared war.  In an attempt to strengthen the Northern argument that commerce on the Great Lakes was not just internally focused, but also incorporated much international trade, Wentworth also had succeeded in having Chicago declared a new Foreign Port of Entry on July 13, 1846, recognizing and legitimatizing direct shipment to and from Canada and Europe.  All of this was to little avail, however, for Polk veoted the 1846 River and Harbor Bill  on August 3, 1846. Polk used the war to try to hide the obvious sectional bias of his veto:

“It would seem the dictate of wisdom under such circumstances to husband our means and not waste them on comparatively unimportant objects… Some of the objects of the appropriation, contained in this bill, are local in their character, and lie within the limits of a single state; and though in the language of the bill they are called harbors, they are not connected with foreign commerce, nor are they places of refuge or of shelter for our navy or commercial marine on the ocean or lake shores.”

The resulting uproar throughout the North was best represented in an editorial in the Chicago Daily Journal  of August 19, 1846:

“The objects of improvement lie north of Mason and Dixon’s line, and would benefit the North and West, whose growing prosperity is hateful to the slave-owners of the South… All other pretenses of objections to the Harbor Bill are idle and vain. The North can and will be no longer hoodwinked.  If no measures for protection and improvement of anything North or West are to be suffered by our Southern masters… a signal revolution will inevitably ensue.  The same spirit and energy that forced emancipation for the whole country from Great Britain will throw off the Southern Yoke… The fiat has gone forth–Southern rule is at an end.”


Andreas, Alfred T. History of Chicago, 3 vols. Chicago, 1884-1886. Reprint, New York: Arno Press, 1975.

Howe, Daniel Walker.  What Hath God Wrought: The Transformation of America, 1815-1848. New York: Oxford University Press, 2007.

Lewis, Lloyd and Henry Justin Smith. Chicago: The History of its Reputation.  New York: Blue Ribbon, 1929.

Pierce, Bessie Louis. A History of Chicago- I. New York: Knopf, 1940.

Putnam, James William. The Illinois and Michigan Canal.  Chicago: University of Chicago Press, 1918.

(If you have any questions or suggestions, please feel free to eMail me at: thearchitectureprofessor@gmail.com)

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