If he chooses to include a tax increase when he proposes his budget later this year, Emanuel is likely to face some public pushback, given recent tax hikes by City Hall, Cook County and state government that will drain hundreds of dollars from the pocketbooks of Chicagoans. But it also may be the mayor's last chance to increase taxes before 2019 — an election year for city officials, who are loathe to ask taxpayers for more money just before voters go to the polls.