Last Updated: Tuesday, Sept. 11, 2012 at 2:18 p.m. EST

After Chicago's education officials and teachers union failed to reach a contract agreement Sunday, the city is experiencing the second day of its first teachers strike since 1987 -- an event that Mayor Rahm Emanuel called "totally unavoidable."

Emanuel defended the city's contract offer and has urged union leaders to stay at the bargaining table until an agreement is reached.

The biggest issues keeping students out of school and teachers on the picket line are teacher evaluations, job security, health benefits and pay. Twenty different proposals were put on the table in the four days prior to the strike -- all rejected, according to Chicago Public Schools (CPS) President David Vitale. Vitale left Monday's meetings optimistic that all issues could be resolved Tuesday, but the president of the teachers union, Karen Lewis, implied otherwise, telling the Chicago Tribune that district leaders offered no new concessions on teacher evaluations or job security.

Though the issues driving this strike are cause for controversy throughout the nation's school districts, experts say it's unlikely that Chicago's conflict will spark strikes in other cities. Read why here.

In preparation for the strike, Chicago set in place a contingency plan last week for parents who have no safe place to send their children. The city has designated 144 schools to remain open for students who have nowhere else to go and to provide food for children who qualify for free or reduced-priced lunch. In addition, parks, libraries and select churches will also offer students a place to go, and the city's transit agency is giving free rides to students until 8:30 p.m.

Though all of the city's public schools are closed, its 118 charter schools are up and running as usual.

The political stakes are high for both Emanuel (who told Governing last year that he pledged to limit teacher strikes) and Lewis. Read how the strike and its eventual outcome could effect both leaders here.

President Barack Obama and presidential candidate Mitt Romney have both taken sides in the stalement, with Obama reportedly supporting the unions and Romney accusing the teachers union of "turn[ing] its back" on students.

Teachers and public officials have increasingly come head-to-head in recent years over the same issues plaguing Chicago right now. Governing investigated the showdown between public employee unions and government leaders last year in a feature called "Are the Unions Winning the Fight?"

The use of data and test scores, which is increasingly used to determine how much teachers get paid and whether they still have a job, has been highly controversial. Governing's Dylan Scott examined the issue earlier this year asking "Can Education Data Build the Perfect Teacher?"

Governing contributor Charles Chieppo has also revisited how to train and keep good teachers in several of his columns.

McClatchy Newspapers contributed to this report.