Jacobs attacks Ernst in new Iowa television ad

The campaign for the Republican Senate nomination just got a little tougher.

Mark Jacobs, the target of attack ads by outside groups for weeks, has now launched one of his own, suggesting in a new television ad that rival Joni Ernst is doing 'strange things” while trying to hide a record of voting for tax increases and missing votes.

Jacobs has out-advertised the five-person field thus far in the primary, but this is the first time that he's gone on the attack on TV.

In the ad, the Jacobs camp uses Ernst's own eye-catching TV ad against her.

Ernst won attention for a new spot that shows her in a leather jacket, riding a motorcycle, then going with a handgun to a shooting range, where a narrator says she is going to 'unload” on the Affordable Care Act.

In the Jacobs spot, a narrator says 'in politics, people do strange things to get elected, especially when they have something to hide.” The ad then goes on to say that Ernst voted to raise the gasoline tax and to tax Internet purchases and that she missed 40 percent of the votes in this year's legislative session.

Ernst is 'firing blanks” when it comes to protecting Iowans, the ad says.

Jacobs and Ernst have been running at the top of polls in the five-way contest for the Republican nomination for the U.S. Senate.

Ernst's campaign responded by pointing to Jacobs' own support for cap-and-trade legislation while he was the head of a Texas-based energy company, along with donations he gave to Democratic political candidates.

It also said that she fought to 'pass the largest tax cut in Iowa history,” referring to the tax overhaul in last year's legislative session.

'Mark Jacobs supports liberal policies, supports liberal Democrats, and if he made it to the U.S. Senate it would be more of the same,” the Ernst campaign said.

The issues at play aren't new, although some have not received significant attention.

Outside groups have been targeting Jacobs for weeks for the comments he made about cap-and-trade. He has since said that he would not support such legislation in the Senate. He also has said most of his political donations have gone to Republicans.

The Jacobs camp has tried to tie the outside groups to Ernst, who has been critical of Jacobs on the same issues. The groups paying for them haven't disclosed who their donors are.

The outside ads, however, were enough to draw the attention of a high-profile Republican.

Former GOP presidential candidate Rick Santorum endorsed Sam Clovis, a Sioux City college professor, in the primary. But in doing so, he also went on to complain about 'so-called conservative groups” trying to 'anoint” a candidate.

Without mentioning Ernst's name, Santorum said that 'a voting record that supports tax increases and not showing up for the job the people entrusted you to do are not conservative principles.”

The polls have said that Clovis is running in third place, following Ernst and Jacobs.

Former U.S. Attorney Matt Whitaker and Scott Schaben, a sales professional from Ames, are also in the race.