EXPLAINER / MIDTERM ELECTION   ((ANIMATION W/ GFX, CAPTIONS)) Republicans now control the presidency and both houses of Congress. They can pass legislation without support from the Democratic Party. They also perform legislative oversight over the executive branch: their party’s president and his administration. Things would change if the midterm elections put Democrats in control of either house of Congress. If Democrats win, the Trump administration’s legislative agenda could slow or stop. Immigration reform, border security, health care, and social programs are in the balance.