The lawsuit alleges that Karen Weaver tried to redirect water crisis funds to her personal campaign.
Obama will get updates from federal officials on the response in Flint, a mostly African-American city where more than 40 percent live in poverty.
The amendment was part of a comprehensive energy bill later approved by the Senate.
Snyder is under pressure to resign over the state's poor handling of a lead water crisis in Flint.
Legal experts say it's tough to prove damage from lead contamination, and the government is claiming immunity from suit.
There were failures on all levels of government, including the U.S. Environmental Protection Agency, a report from the governor-appointed task force said.
The lawsuits filed on Thursday in Genesee County court, along with nine filed earlier in March, cover 50 children allegedly suffering from lead poisoning from drinking Flint water.
The two Democrats will face off in a debate, and Marco Rubio will participate in a one-man town hall.
The residents allege that officials failed to take action to end the ongoing contamination.
The candidates met Thursday in Detroit, which is 70 miles from the ongoing water crisis in Flint, Michigan.
Federal criminal statutes may apply. At the state level, individuals could be prosecuted for failure to carry out their legal responsibilities.
The emails were sent months before the governor said he learned of the outbreak and the possible reasons behind it.
To address tragedies like Flint, state legislatures need to invest in research universities.
Michigan's governor has borne the brunt of the blame, but there's plenty to go around.
Susan Hedman's resignation comes as criticism of both the state and federal response to the toxic-water crisis continues to grow.
Drinking water in Flint, Michigan, was contaminated with high levels of lead after the state switched supply sources.
One of Snyder's aides warned the crisis could become "political football."
Rev. Jesse Jackson said on Sunday that Flint, Michigan is a "disaster zone."
The lifetime loss of income from diminished IQ for the 25,000 children amounts to half a billion dollars.