The period that opened with adoption of a new state constitution saw continued growth in agricultural and industrial production. The state’s population grew rapidly with settlers from other states, but especially due to immigration from German states and Ireland. Growing debate over the role of slavery in the life of the nation raised tensions to a level that finally sundered the Union. As the home of Stephen A. Douglas—a national leader of the Democrats—and of a skilled Republican challenger in the form of Abraham Lincoln, Illinois was a crucial battleground during the decade that ended in war. The state contributed mightily to the Union cause, providing its commander-in-chief, numerous military leaders, more than 220,000 soldiers and sailors, and large volumes of agricultural and manufactured products.