At a point when most of the media is treating the race between Barack Obama and Hillary Clinton as a highly competitive one, Obama has slowly but steadily increased his delegate lead to a point that should sustain his frontrunner status through the remainder of the contest.

While the precise numbers will vary from one semi-official count to the next — the Obama camp has an embarrassing habit of inflating already good numbers to sometimes ridiculous extremes — there is general agreement that this is about where the candidates now stand:

Barack Obama:1,618 delegates(1,411 pledged/207 declared super delegates)

Hillary Clinton:1,479 delegates(1,242 pledged/ 237 declared super delegates)

Since the mixed-results day of March 4 (good headlines and momentum for Clinton, an even split among delegates for Obama), the Illinois senator has expanded his lead bit by bit — steadily upping his Texas numbers as caucus results get sorted out, winning big in small states such as Mississippi and Wyoming and scoring nicely at last weekend’s Iowa county caucuses (the next stage inthat state’s long process) where supporters of John Edwards swung heavily in his direction. Scattered improvements in old results as counts have been completed — one more delegate from New York, five more from California — are the icing on Obama’s cake.

It all adds up to an almost 140-vote delegate spread in favor of the Obama. (Even the most Clinton-friendly counts have him up by roughly 120.)

Before this month of March is done, Obama could well have a lead of more than 150 delegates.

That is twice the lead that the senator had after his last really good day on February 19, when he won a surprisingly wide win in Wisconsin.

In other words, even as his campaign hits speed bumps (as were experienced in Ohio, Rhode Island and to some extent Texas) it continues to move forward.

How far forward?

Obama is quietly moving beyond the range where even serious primary losses are unlikely to narrow his lead to under 100 delegates.

Pennsylvania, which will hold its primary April 22, has only 158 delegates at stake. More than two-thirds of those delegates will be chosen at the congressional district level — including a number where African Americans, suburbanites and college-town voters dominate — and that means that while Obama may lose the state he will win plenty of delegates.

An best-case scenario has Clinton coming out of Pennsylvania with a gain of 35 delegates. It will probably be closer to 25.

Then the schedule turns, generally if not completely, in Obama’s favor.

Obama should do fine in Guam (9 delegates) on May 3 — probably a win, based on his Pacific roots and ties.

Obama is likely to win more delegates on May 6, when primaries are held in North Carolina (134) and Indiana (84). North Carolina should be another good southern state for him. Indiana is more complex — at once a neighbor state to Illinois and an old-school industrial state with an edgy history of racial politics like Ohio.

Clinton win probably win West Virginia (39) on May 13, although Obama will hold his own and could actually move into a lead if the United Mineworkers and the United Steelworkers — both John Edwards unions — were to go his way.

Bet on a Kentucky (60) to go for Clinton May 20, but Obama should secure a solid Oregon (65) win that day. Split the delegates about evenly, but with a slight advantage for the Illinoisan.

On June 1, Clinton is supposed to win Puerto Rico (63), but don’t rule out a surprise. (The Obama camp is figuring out that not all Hispanics vote alike, and they are developing smart messaging for America’s Caribbean voters.)

Obama should win both Montana (24) and South Dakota (23) on June 3. He’s got strong farm-belt support — with especially good ties to some key players in the National Farmers Union, which is strong in the northern Plains states — and former South Dakota Senator Tom Daschle has wired his native state for the man he hopes will give him a key Cabinet post.

Add it all up and the best bet is that, even without super-delegate commitments and switches (which will, increasingly, go his way), Obama should finish the regular calendar with a lead somewhere in the range of 225 to 250 delegates.

Then come the revotes in Michigan and, maybe, Florida.

Clinton could win both states, but don’t look for a blowout in either. She lost 45 percent on the January 15 primary vote in Michigan and 50 percent of the January 29 primary vote in Florida.

The bottom line: This race will go on. Clinton will have a few more good days, perhaps some very good days in Pennsylvania, West Virginia, Puerto Rico and Florida. But Obama’s delegate cushion is getting strong enough to sustain even relatively serious setbacks.

Clinton may yet stake a claim on momentum if she gets a pattern of wins in big states such as Pennsylvania, Michigan and Florida. But the Clinton camp has not endeared itself to key players in the House and Senate who will step in at critical points to tip the scale back in Clinton’s direction.

Nothing about this race is ever written in stone. But the quiet growth of Obama’s delegate cushion is the big story of the moment — far bigger, in fact, than the sensationalized stories about what Geraldine Ferraro or Jeremiah Wright Jr. have or have not said.