What to know

• Senator Susan Collins, one of the most vulnerable Republicans in the midterms, clashed with the Democratic challenger Troy Jackson over President Trump, ICE and more.S1
• Tuesday marked the first of four debates between Collins and Jackson.S2
• The debate in a race for a critical Senate seat featured lots of talk about President Trump, high prices and the war in Iran.S3
• Republican Sen. Susan Collins and Democratic challenger Troy Jackson debated for the first time Tuesday in Maine, trading attacks over President Donald Trump, the cost of living and abortion in one of the most closely watched Senate races in the country.S4