Senate Minority Leader Mitch McConnell is under attack from the left and the right.

The Kentucky Republican, his approval rating in the tank, will have to fend off a primary challenge next year just to get into the general election, where he will likely face Kentucky Secretary of State Alison Lundergan Grimes. As two polls out this week showed, his path to re-election is by no means a cake walk.

Each survey showed the general election contest within the margin of error, leaving McConnell and Grimes essentially deadlocked. A Mellman Group poll conducted for the Grimes campaign and released Wednesday showed the candidate leading McConnell 44 percent to 42 percent. A PPP survey released one day later had Grimes up 45 percent to 44 percent.

Those results were enough for the Cook Political Report to bump the race from leaning Republican to being a toss-up.

McConnell's horrible approval rating is the biggest reason this race is even close at this point. Kentucky is a deep red state that last November went for Romney by a 23-point margin. The state hasn't elected a Democratic senator since the 1970s.

Each of the two latest surveys found that a majority of voters disapproved of his job performance. And last year, a PPP poll named McConnell the least popular senator in the country.

McConnell, however, should still be considered the favorite because of his incumbency. Though voters hate Congress, they tend to stick with the candidate they know; in 2004, voters sent 98 percent of incumbents back to Congress, according to OpenSecrets.

Here's The New Republic's Nate Cohn with more on that:

Mitch McConnell is a clear favorite because he's a Republican incumbent running in a red state, assuming he wins the primary. Perhaps this obvious point is being overlooked because of its simplicity, but the fact is that incumbents don't often lose on friendly terrain. No blue state Democratic incumbent lost in 2010. The only red state Republican incumbent who lost in 2008 was Ted Stevens, who was battling corruption charges and still only lost by a narrow margin. In 2006, Republican incumbents lost painfully close Senate races in Montana and Missouri, but it's worth recalling that those were also the two closest red states of the 2008 presidential election, where McCain won by 2.38 and 0.13 points, respectively. In comparison, Kentucky went to McCain by 16 points and Romney by 23. [New Republic]

As Cohn also noted, the path to a Democratic victory in Kentucky has gotten even smaller in recent years. While statewide Democratic campaigns used to rely on coal country for a huge share of their votes, that edge has dried up — and will continue to do so if Republicans effectively harness the "War on Coal" message against President Obama.

McConnell also has an enormous war chest. He ended the first quarter of the year with $8.6 million in cash on hand, twice what all but two other senators who will be up for re-election next year could boast.

McConnell could potentially face a tougher primary fight, since polls have shown voters itching for a more conservative challenger. Yet primary campaigns against sitting senators rarely work, and its hard to imagine a relatively unknown businessman toppling the party's top senator.

If McConnell passes that first test, his path to re-election should smooth considerably as reluctant GOP voters line up behind him to keep one of their own in Washington.