Ron Paul vows to campaign despite Romney lead

Ron Paul said today he'll continue his presidential campaign "in a modified way" even if Mitt Romney obtains the 1,144 delegates needed for the GOP nomination.

"You don't quit because you happen to be behind," Paul, a Texas congressman, said on CNBC. "You want to see how you can do. Who knows? Maybe somebody will stumble."

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Paul said he wants to be able to go to the Republican National Convention in Tampa to give his supporters a voice.

Unless something unusual happens, Romney will add to his massive delegate lead tomorrow when primaries occur in Pennsylvania, New York, Connecticut, Delaware and Rhode Island.

Romney has been considered the likely GOP nominee since Rick Santorum dropped out of the race after Easter, and he has amassed 697 delegates. Paul and Newt Gingrich continue to campaign.

According to an AP tally, Gingrich has 137 delegates and Paul has 67.

Don't expect Paul to endorse Romney, either. Paul told CNBC that Romney is "part of that whole crowd of politicians, Republicans and Democrats, that are much closer together than most people realize."