In a fiat money situation, there is typically little problem with a deficit and national debt. There is only a problem when the deficit is larger than GDP growth, because in that situation the real value of the debt is actually increasing, and it is then when the opportunity costs of having a deficit exceed the benefits. This is because now more value by the year is being trapped in the debt via securities than total value in the economy. And moreover, since money has a multiplicative effect, this tremendously hampers growth prospects and likewise the overall business environment.
(Edit: in my political opinion, that means that the government should seriously consider austerity policy in order to make the deficit lower than GDP growth.)