By By Steve Peoples and Jonathan Lemire The Associated Press DORAL, Florida - Suddenly armed with fresh political ammunition, Donald Trump and anxious Republicans across the nation seized on spiking health care costs Tuesday in a final-days effort to spark election momentum. The Republican presidential nominee, trekking across must-win Florida, insisted "Obamacare is just blowing up" after the government projected sharp cost increases for President Barack Obama's signature health care law.