Last night, Sen. Hillary Clinton claimed that “the tide has turned” upon her 10-point victory in the hard-fought Pennsylvania primary.

But it’s more likely that she merely delayed the wave of momentum that is waiting to carry Sen. Barack Obama to the Democratic nomination.

This is not to diminish Hillary Clinton’s win or Pennsylvania’s importance altogether. Obama’s loss in another big state and the margins by which he lost among blue-collar and rural voters raise lingering questions.

However, as Democratic delegates are allotted proportionally according to the vote, Clinton’s Pennsylvania win does little to cut into Obama’s lead among pledged delegates or his advantage in the popular vote count.

Of course, if one counts Florida in the popular vote total, Barack Obama’s lead is considerably smaller. If you count Michigan and Florida - as Clinton aides surely will in their arguments - Obama no longer has a lead at all.

Pennsylvania win in hand, where does Hillary Clinton go from here?

So look for Clinton to head into the next round contests with the renewed big state theory - that Obama can’t win states like Pennsylvania and Ohio that Democrats will need to regain the White House in November.

On the flip side of that, Obama expands the electoral map in ways Clinton can’t. But Obama’s best strategy is to make these arguments moot with two huge wins on May 6, when Indiana and North Carolina take center stage.

It’s doubtful that Clinton can overtake Obama in North Carolina, where he enjoys a double-digit lead in polls. But the Clintons will campaign there to try to make it close - and keep him away from Indiana, where polls are about even.

Obama would love a victory in Indiana to prove he can win a large rust belt state and bolster his case that he can beat Sen. John McCain. Any victory also helps immensely in the tightening popular vote battle.

Until he posts another important victory - for symbolic and logistical reasons - the door is left ajar, no matter how small the crack may be.

Clinton will continue to challenge Obama’s electability in her argument to the superdelegates. He must erase any doubts via the only truly conclusive, indisputable means - votes. Bring on May 6.