"And so we have to be careful with looking at additional stimulus that we don't provoke an increase in the bond rate and then offset a lot of the stimulus we've already got"

Franklin Raines is cautioning us to be conscious of the prospective repercussions of introducing extra stimulus into the economy. He is describing the bond rate, which is the rates of interest at which the federal government obtains money from the general public. If the bond rate boosts, it will balance out the stimulus that has currently been put in location. This could have an unfavorable impact on the economy, as it would make it more pricey for the government to obtain money, and might result in a decline in economic activity. For that reason, it is essential to be careful when presenting extra stimulus, as it could have unintentional repercussions. Raines is warning us to be conscious of the potential impacts of presenting extra stimulus, and to think about the potential effect on the bond rate prior to doing so.