"making it all the more likely" is a correct and usable phrase in written English
It is typically used to indicate that something has increased the probability or chance of something happening. It can also be used to emphasize the likelihood of something occurring. Example: The favorable weather forecast for the weekend is making it all the more likely that we will have a successful outdoor event.
It is clear that Mr. Emanuel has an enormous challenge ahead, making it all the more likely that drastic, painful sorts of change are unavoidable.
But, for now, there's not much original local reporting on the Web, making it all the more likely that local government will get a pass.
-- The handful of the worst hurricanes we've seen this year all have something in common: They intensified rapidly, making it all the more likely the impact will cause the worst-case scenario.
Mr. Mann, of the Brookings Institution, said the $87 billion price tag had caused "sticker shock on Capitol Hill," drawing attention to the deficit and making it all the more likely that Democrats will win yet another battle: the battle to keep Mr. Bush's tax cut from becoming permanent.
The next several years will see the debut of many next generation telescopes like the James Webb Space Telescope and huge terrestrial 'scopes in Hawaii, Chile and elsewhere that will complement the search, making it all the more likely that we really will be able to say relatively soon that we are not alone.
Research shows that Americans are more likely than Europeans to believe that "life is perfectible" (in other words, that pain is avoidable), making it all the more likely that a Boomer might seek out substances to deal with the pains of aging.
This makes it all the more likely that expectations, and thus actual inflation, will become entrenched below target.
And that makes it all the more likely that Simon Cowell's new show, "The X Factor" will do well.
That makes it all the more likely that Democratic candidates will avoid bringing up the issue with voters.
That dark future has long been a lurking possibility, and recent events make it all the more likely.
More likely, it was, as her spokeswoman claimed, just a jacket, but that makes it all the more questionable.
