Jacquelyn Martin, Associated Press
Some in the GOP fear that conservative activists would have unrealistic expectations if Republicans run both the House and Senate.

WASHINGTON — How much difference would it make if Republicans win control of the Senate this fall?

Some in the GOP fear that conservative activists would have unrealistic expectations if Republicans run both the House and Senate.

President Barack Obama could veto bills. Senate Democrats could block many measures with filibusters that make final votes impossible.

Republicans could use their control to highlight the parties' differences by forcing Obama to veto conservative-backed bills. That could include efforts to repeal the president's health care law.

Senate Republicans could join the House in investigating a host of incidents and policies embarrassing to the Obama administration.

They also could block Obama's nominees for judgeships and top administration posts.

Democrats say Republicans could overplay their hand by voting to slash programs that many Americans like.