In Washington, President Lincoln and Secretary of War Edwin M. Stanton decided that the defeat of Jackson was an immediate priority (even though Jackson's orders were solely to keep Union forces occupied away from Richmond). They ordered Irvin McDowell to send 20,000 men to Front Royal and Frémont to move to Harrisonburg. If both forces could converge at Strasburg, Jackson's only escape route up the Valley would be cut. The immediate repercussion of this move was to abort McDowell's coordinated attack with McClellan on Richmond. Starting on May 29, while two columns of Union forces pursued him, Jackson started pushing his army in a forced march southward to escape the pincer movements, marching forty miles in thirty-six hours. His army took up defensive positions in Cross Keys and Port Republic, where he was able to defeat Frémont and James Shields (from McDowell's command), respectively, on June 8 and June 9.