Why do the US midterms matter for Trump and Congress?

According to Al Jazeera, because members of the House serve two-year terms, all 435 seats in the chamber are up for election on November 3.[1] Al Jazeera also says Republicans currently hold a slim majority of 218-214 seats in the House[2] and a 53-47 majority in the Senate.Al Jazeera notes that laws typically need a supermajority of 60 votes in the Senate to overcome a process known as the filibuster.[1] It says this last happened in January 2021, during Trump's first term.[1]Al Jazeera reports that Republican majorities helped Trump pass a sweeping 2025 tax bill[1] that boosted ICE funding and cut back some publicly funded healthcare. The outlet says, however, that he has been unable to pass his signature federal voter identification law, dubbed the "SAVE America Act"[1].According to Al Jazeera, Republicans have defied Trump, particularly on tariffs[1], and a few have voted to assert congressional authority over the US-Israel war with Iran.Al Jazeera cites a Reuters/Ipsos poll in which 47 percent chose Democrats, while 35 percent opted for Republicans.[2] Trump called the vote "the Most Important Midterm Elections in our Country's History"[3].