Outside spending groups have poured millions of dollars into Illinois Democratic congressional primaries ahead of Tuesday's elections, with the American Israel Public Affairs Committee (AIPAC) and artificial intelligence-related super PACs leading the investment.

AIPAC and its affiliated political action committees have spent at least $13.7 million across four Illinois races, according to an investigation by WBEZ, Chicago's public radio station. The pro-Israel lobbying organization has channeled funds through two super PACs with names that do not reference Israel: Elect Chicago Women and Affordable Chicago Now.

The four Democratic congressional primaries in and around Chicago represent one of the largest tests of outside spending influence in the current election cycle. The races have attracted significant attention due to the substantial financial investments from various interest groups.

In addition to AIPAC's spending, artificial intelligence industry super PACs have also made substantial investments in the Illinois primaries, though specific amounts were not detailed in available reports.

The heavy outside spending reflects the strategic importance these groups place on influencing the composition of Congress. AIPAC, one of Washington's most influential lobbying organizations supporting Israel, has been expanding its electoral involvement in recent years through affiliated political action committees.

The Illinois primaries will serve as a significant indicator of how effective large-scale outside spending can be in determining electoral outcomes, particularly in competitive Democratic races where multiple candidates are vying for party nominations.