Mitt Romney sought to portray President Obama as desperately looking for “a twig to hold on to” with the economy while campaigning in swing-state Colorado on Tuesday.

But as the Republican challenger renewed focus on economic issues, his presidential campaign was besieged with questions about Donald Trump’s controversial “birther” comments.

Romney hit many of his core economic talking points while stumping in Craig, Colo., arguing that the “president’s policies made it harder for America to get on its feet again.”