Published: Apr 04, 2012 10:13 PM EDT

Mitt Romney has widened his lead in the Republican Presidential race after three impressive wins.

The GOP hopeful now seems to have a firm grip on the race. Romney is trying to convince the Republican party he is the presumptive nominee, but his opponents don't appear ready to leave the race.

Mitt Romney is looking past his Republican opponents and focusing on the general election.

"Join me in the next step toward that destination of November 5th, when across America, we can give a sigh of relief and know that the promise has been kept," Romney said.

Romney swept Tuesday's primaries in Wisconsin, Maryland and the District of Columbia. He now has more than half the delegates needed to secure his party's nomination. His supporters say the race has reached the point where Rick Santorum and the other candidates should step aside.

"I think it's clear that he's the nominee. I also hope that Rick Santorum would understand that it's time for a graceful exit," said Senator John McCain of Arizona.

But Rick Santorum says he's staying in the race. He's focusing his campaign on upcoming primaries in the northeast
including his home state of Pennsylvania.

"This isn't half time, no marching bands, the clock starts tonight. We have three weeks to go out in Pennsylvania and win this state," Santorum said.

Newt Gingrich and Ron Paul are far behind in the delegate count. Santorum appears to be the only real competion left,  but even some of his supporters don't believe he can win.

Two thirds of Republicans who voted for Santorum in the Wisconsin primary, say they actually believe Romney will be the nominee.

Pennsylvania, New York, Connecticut, Delaware and Rhode Island all hold primaries on April 24th.